[[matematik:start|Tilbage til matematik]] ---- * [[Kolakoski sequence]] * [[Ulam numbers]] ===== On-Line Encyclopedia of Integer Sequences ===== * [[b-file analyse]] ==== Registrans ==== * [[https://oeis.org/wiki/Special:ConfirmAccounts|Confirm]] ---- Jeg vil måske lave en DVD med OEIS. [[https://www.zoomsearchengine.com/flyingant/index.html|Flyingant]] skal være på dvd'en. ---- Sekvenser med 2,3 eller 4 forskellige værdier. Nogle af dem kunne være interessante grafiske. ^Forskellige værdier^Kandidater^Gode| ^2^A000480, A000484, A000494, A001468, A002819, A002909, A002928, A002930, A003589, A003687, A003782, A003842, A003849, A003982, A004539, A004547, A004555, A004569, A004593, A004601, A004609, A004641, A005171, A005369, A005614, A005713, A006337, A006338, A006340, A006345, A006461, A006466, A006513, A006836, A006928, A007061, A007362, A007421, A007424, A007538, A008683, A008869, A008870, A008966, A009058, A010051, A010052, A010054, A010055, A010056, A010057, A010058, A010059, A010060^A000002, A001030, A001285, A284680| ^3^A005678, A005679, A005680, A006460, A007413, A007423, A007540, A007706, A007877, A007945, A007968, A008741, A008868, A009501, A009529, A010121, A010122, A010130, A010133, A010141, A010143, A010152, A010153, A010170, A010194, A010195, A010227, A010331, A010872, A010882, A011187, A011770, A011771^A001176, A003137, A003270, A004530, A004540, A004548, A004556, A004570, A004578, A004586, A004594, A004602, A004610| ^4^ ^A005681| ---- Sekvenser, som jeg har bidraget til: * [[https://oeis.org/A030101|A030101]] a(n) is the number produced when n is converted to binary digits, the binary digits are reversed and then converted back into a decimal number. * [[https://oeis.org/A055748|A055748]] A chaotic cousin of the Hofstadter-Conway sequence * [[https://oeis.org/A247820|A247820]] Numbers n such that sigma(2n-1) is a prime p. * [[https://oeis.org/A246910|A246910]] Numbers n such that sigma(n+sigma(n)) = 3*sigma(n). * [[https://oeis.org/A265650|A265650]] Removing the first occurrence of 1, 2, 3, ... reproduces the sequence itself. Each run of consecutive removed terms is separated from the next one by a term a(k) <= a(k-1) such that floor(sqrt(a(k))) equals the length of the run. * [[https://oeis.org/A160029|A160029]] Primes of the form 2^(2^n)+51. * [[https://oeis.org/A169595|A169595]] Primes p such that sigma(p+2)=sigma(p-2). * [[https://oeis.org/A169596|A169596]] Primes p such that sigma(p+3)=sigma(p-3). ---- Interessante sekvenser * [[https://oeis.org/A001228|A001228]] [[wp>Sporadic_group|Orders of sporadic simple groups]] * [[https://oeis.org/A003001|A003001]] Smallest number of multiplicative persistence n * [[https://oeis.org/A005132|A005132]] [[https://mathlesstraveled.com/2016/06/12/the-recaman-sequence|Recaman sequence]] * [[https://oeis.org/A005150|A005150]] [[wp>Look-and-say_sequence|Look-and-Say]] * [[https://oeis.org/A005602|A005602]] [[wp>Cunningham_chain|Smallest prime beginning a complete Cunningham chain of length n (of the first kind)]] * [[https://oeis.org/A005845|A005845]] [[wp>Lucas pseudoprime]] * [[https://oeis.org/A006945|A006945]] [[wp>Miller–Rabin_primality_test|Smallest odd number that requires n Miller-Rabin primality tests]] * [[https://oeis.org/A008284/A008284]] Triangle of partition numbers * [[https://oeis.org/A014577|A014577]] [[wp>Regular paperfolding sequence]] * [[https://oeis.org/A030101|A030101]] Converted to binary digits, reversed and converted back into a number. * [[https://oeis.org/A036057|A036057]] Friedman numbers: can be written in a nontrivial way using their digits and the operations + - * / ^ and concatenation of digits (but not of results). * [[https://oeis.org/A038219|A038219]] [[wp>Ehrenfeucht–Mycielski sequence]] * [[https://oeis.org/A036236|A036236]] Smallest integer k > 0 such that 2^k mod k = n, or 0 if no such k exists. * [[https://oeis.org/A045911|A045911]] Neither a cube nor the sum of a nonnegative cube and a prime. * [[https://oeis.org/A055748|A055748]] [[wp>Hofstadter_sequence#Pinn_Fi.2Cj.28n.29_family|A chaotic cousin of the Hofstadter-Conway sequence]] * [[https://oeis.org/A090822|A090822]] [[wp>Gijswijt's sequence]] * [[https://oeis.org/A096555|A096555]] [[wp>RANDU]] * [[https://oeis.org/A114440|A114440]] Numbers which divided by the sum of their digits (Harshad or Niven numbers) give integers which are also divided by the sum of their digits (until a single digit Harshad remains). * [[https://oeis.org/A119566|A119566]] Periodic table of elements associated with the Look-and-Say sequence * [[https://oeis.org/A121977|A121977]] Numbers with a distinct frequency for each decimal digit. * [[https://oeis.org/A131884|A131884]] Numbers conjectured to have an infinite, aperiodic, aliquot sequence. * [[https://oeis.org/A134204|A134204]] Leroy Quet's prime-generating recurrence. * [[https://oeis.org/A179243|A179243]] Numbers n that have three terms in their Zeckendorf representation. ---- * [[http://arxiv.org/abs/1101.4470|Sloan's Gap]] * [[http://arxiv.org/abs/0805.2128|8 Hateful sequences]] * [[http://oeis.org/toothlist.html|Catalog of Toothpick and Cellular Automata Sequences]] * [[https://arxiv.org/pdf/1704.00007.pdf|The Repeated Divisor Function and Possible Correlation with Highly Composite Numbers]]