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 A324814 Numbers n > 1 for which sigma(A156552(n)) == 2 (mod 4). 4
 6, 14, 15, 18, 33, 35, 38, 42, 54, 58, 65, 69, 70, 75, 77, 90, 93, 102, 106, 110, 119, 130, 143, 145, 150, 162, 165, 174, 177, 185, 190, 209, 217, 221, 230, 231, 234, 242, 245, 273, 285, 287, 290, 294, 299, 305, 323, 330, 338, 350, 357, 375, 378, 390, 407, 410, 414, 434, 437, 450, 455, 465, 469, 473, 483, 493, 494, 507 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Sequence A005940(1+A191217(n)), n >= 1, sorted into ascending order. LINKS PROG (PARI) 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 by David A. Corneth A324824(n) = ((n>1)&&(2==(sigma(A156552(n))%4))); A324824(n) = (2==(A323243(n)%4)); \\ Alternatively. for(n=1, oo, if(A324824(n), print1(n, ", "))); CROSSREFS Cf. A000203, A005940, A191217, A324812, A324813, A324824 (characteristic function). Sequence in context: A184998 A322561 A079010 * A015822 A023883 A230873 Adjacent sequences:  A324811 A324812 A324813 * A324815 A324816 A324817 KEYWORD nonn AUTHOR Antti Karttunen, Mar 16 2019 STATUS approved

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Last modified June 2 10:57 EDT 2020. Contains 334771 sequences. (Running on oeis4.)