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.

A332451 a(n) = A005940(1+A048724(A156552(n))).

Original entry on oeis.org

1, 4, 9, 6, 25, 16, 49, 10, 15, 36, 121, 54, 169, 100, 81, 14, 289, 24, 361, 150, 225, 196, 529, 250, 35, 484, 21, 294, 841, 64, 961, 22, 441, 676, 625, 90, 1369, 1156, 1089, 490, 1681, 144, 1849, 726, 375, 1444, 2209, 686, 77, 60, 1521, 1014, 2809, 40, 1225, 1210, 2601, 2116, 3481, 486, 3721, 3364, 735, 26, 3025, 400
Offset: 1

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Author

Antti Karttunen, Feb 15 2020

Keywords

Crossrefs

Cf. A000290, A003961, A005117 (gives the positions of squares), A005940, A008836, A010052, A048724, A156552, A277010, A293448, A332449, A332450.
Permutation of A028260.
Cf. A332460 for complementary sequence (after its initial 1).

Programs

  • PARI
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ From A005940
    A048724(n) = bitxor(n, 2*n); \\ From A048724
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A332451(n) = A005940(1+A048724(A156552(n)));

Formula

a(n) = A005940(1+A048724(A156552(n))).
a(p) = p^2 for all primes p.
For all squarefree numbers u, a(u) = A332449(u) and A010052(a(u)) = 1.
a(A003961(n)) = A003961(a(n)).
a(A293448(n)) = A293448(a(n)).
a(A332450(n)) = A332450(A003961(n)); A332450(a(n)) = A003961(A332450(n)).
A008836(a(n)) = +1 for all n.