cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A322863 Permutation of natural numbers: a(0) = 1; for n >= 1, a(n) = A005940(1+A122111(n)).

Original entry on oeis.org

1, 2, 3, 5, 4, 7, 9, 11, 6, 10, 25, 13, 15, 17, 49, 21, 8, 19, 16, 23, 35, 55, 121, 29, 27, 36, 169, 50, 77, 31, 81, 37, 12, 91, 289, 225, 30, 41, 361, 187, 125, 43, 625, 47, 143, 147, 529, 53, 45, 154, 90, 247, 221, 59, 28, 1225, 343, 391, 841, 61, 105, 67, 961, 605, 18, 5929, 2401, 71, 323, 551, 525, 73, 22, 79, 1369, 84, 437, 429, 14641, 83
Offset: 0

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Author

Antti Karttunen, Dec 30 2018

Keywords

Comments

Note the indexing: the domain starts from 0, but the range excludes zero.

Crossrefs

Inverse permutation: A322864.

Programs

  • PARI
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A322863(n) = if(!n,1,A005940(1+A122111(n)));

Formula

a(0) = 1; for n >= 1, a(n) = A005940(1+A122111(n)).
For all n >= 1:
a(prime(n)) = prime(1+n).
A001222(a(n)) = A322867(n).