A062824 a(n) = Ch(A005117(n)) where Ch(n) is Chowla's function and A005117(n) are the squarefree numbers.

0, 0, 0, 0, 5, 0, 7, 0, 0, 9, 8, 0, 0, 10, 13, 0, 15, 0, 41, 0, 14, 19, 12, 0, 21, 16, 0, 53, 0, 25, 0, 20, 0, 16, 22, 31, 0, 0, 33, 18, 77, 0, 26, 73, 0, 0, 39, 18, 89, 0, 43, 0, 22, 45, 32, 0, 20, 34, 49, 24, 0, 0, 113, 0, 86, 55, 0, 0, 105, 40, 0, 125, 28, 61, 24, 63, 44, 0, 46, 121, 0, 26, 69, 0, 149, 0, 50, 73, 24, 34, 75, 0

Offset

1,5

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A048050(A005117(n)). - Amiram Eldar, Mar 10 2024

Mathematica

chowla[n_] := DivisorSigma[1, n] - n - 1; chowla[1] = 0; chowla /@ Select[Range[150], SquareFreeQ] (* Amiram Eldar, Mar 10 2024 *)

Prog

(PARI) j=[0]; for(n = 2, 150, if(issquarefree(n), j = concat(j, sigma(n)-n-1))); j

Crossrefs

Cf. A005117, A048050.

Sequence in context: A291800 A091685 A349298 * A292904 A271228 A281528

Adjacent sequences: A062821 A062822 A062823 * A062825 A062826 A062827

Keyword

easy,nonn

Author

Jason Earls, Jul 20 2001

Extensions

a(1) corrected by Amiram Eldar, Mar 10 2024

Status

approved