A379950 Numbers k such that k^2 is an odd primitive abundant number (A006038).

585, 32085, 41925, 46665, 121605, 134589, 181305, 212175, 388455, 495465, 544065, 839865, 1061565, 1152921, 1165515, 1243275, 1247103, 1335411, 1676829, 2151075, 2290869, 2478075, 2771835, 2838165, 3016725, 3122847, 3156795, 4571415, 4738041, 5153841, 5558985, 6125049, 7471425, 7676775, 7780101, 7822425, 8259867

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..3500 (terms 1..725 from Antti Karttunen)

Formula

a(n) = A000196(A379949(n)).

Prog

(PARI) isok(k) = if(!(k % 2), 0, my(f = factor(k)); for(i = 1, #f~, f[i, 2] *= 2); if(sigma(f, -1) <= 2, return(0)); for(i = 1, #f~, f[i, 2] -= 1; if(sigma(f, -1) > 2, return(0)); f[i, 2] += 1); 1); \\ Amiram Eldar, Mar 12 2025

Crossrefs

Square roots of A379949.

Subsequence of A174830.

Cf. A000196, A006038.

Sequence in context: A024380 A258331 A352979 * A022243 A217446 A369861

Adjacent sequences: A379947 A379948 A379949 * A379951 A379952 A379953

Keyword

nonn

Author

Antti Karttunen, Jan 07 2025

Status

approved