A348934 Numbers k congruent to 1 or 5 mod 6, for which A348930(k^2) > k^2.

5, 11, 17, 23, 25, 29, 41, 47, 49, 53, 55, 59, 71, 83, 85, 89, 101, 107, 113, 115, 121, 125, 131, 137, 145, 149, 167, 169, 173, 179, 187, 191, 197, 205, 227, 233, 235, 239, 245, 251, 253, 257, 263, 265, 269, 275, 281, 289, 293, 295, 311, 317, 319, 343, 347, 353, 355, 359, 361, 383, 389, 391, 401, 415, 419, 425, 431

Offset: 1

Author

Antti Karttunen, Nov 04 2021

Keywords

• nonn

Comments

See comments in A348933.

Links

• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A348930, A348932, A348933, A348936.

Programs

Mathematica

s[n_] := n / 3^IntegerExponent[n, 3]; Select[Range[450], MemberQ[{1, 5}, Mod[#, 6]] && s[DivisorSigma[1, #^2]] > #^2 &] (* Amiram Eldar, Nov 04 2021 *)

PARI

A038502(n) = (n/3^valuation(n, 3));
A348930(n) = A038502(sigma(n));
isA348934(n) = ((n%2)&&(n%3)&&(A348930(n^2)>(n^2)));