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matematik:oeis

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On-Line Encyclopedia of Integer Sequences

Registrans


Jeg vil måske lave en DVD med OEIS. Flyingant skal være på dvd'en.


Sekvenser med 2,3 eller 4 forskellige værdier. Nogle af dem kunne være interessante grafiske.

Forskellige værdierKandidaterGode
2A000480, 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, A010060A000002, A001030, A001285, A284680
3A005678, 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, A011771A001176, A003137, A003270, A004530, A004540, A004548, A004556, A004570, A004578, A004586, A004594, A004602, A004610
4 A005681

Sekvenser, som jeg har bidraget til:

  • 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.
  • A055748 A chaotic cousin of the Hofstadter-Conway sequence
  • A247820 Numbers n such that sigma(2n-1) is a prime p.
  • A246910 Numbers n such that sigma(n+sigma(n)) = 3*sigma(n).
  • 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.
  • A160029 Primes of the form 2^(2^n)+51.
  • A169595 Primes p such that sigma(p+2)=sigma(p-2).
  • A169596 Primes p such that sigma(p+3)=sigma(p-3).

Interessante sekvenser


matematik/oeis.txt · Last modified: 2020/11/22 00:55 by martin