A333847 a(n) = A063514(A028982(n)).

0, 0, 1, 3, 1, 7, 3, 11, 15, 7, 15, 13, 31, 3, 13, 3, 17, 23, 63, 19, 39, 27, 63, 65, 43, 69, 127, 51, 35, 91, 81, 39, 15, 1, 237, 9, 51, 255, 47, 115, 105, 281, 87, 33, 117, 121, 87, 33, 59, 207, 181, 63, 235, 511, 141, 409, 243, 517, 87, 343, 295, 249, 75, 615, 363

Offset: 1

Author

Michel Marcus, Apr 08 2020

Keywords

• nonn

Comments

Except for the first 2 terms, all terms are odd.

Links

• Michel Marcus, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A028982 (squares and twice squares), A063514 (sigma(n) mod phi(n)), A072808.

Programs

PARI

lista(nn) = {for (n=1, nn, if (issquare(n) || (!(n%2) && issquare(n/2)), print1(sigma(n) % eulerphi(n), ", ");););}