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 A303996 Numbers whose sum of divisors is the sixth power of one of their divisors. 6
 1, 17490, 19410, 22578, 2823492, 162523452, 165982908, 216731788, 221416468, 221940628, 226768440, 230365560, 232815480, 234896520, 238942920, 240737160, 241362120, 242067720, 242454120, 242655720, 258182910, 264254670, 268298190, 272819070, 277297710, 286008510 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Subset of A019424. LINKS Table of n, a(n) for n=1..26. EXAMPLE Divisors of 17490 are 1, 2, 3, 5, 6, 10, 11, 15, 22, 30, 33, 53, 55, 66, 106, 110, 159, 165, 265, 318, 330, 530, 583, 795, 1166, 1590, 1749, 2915, 3498, 5830, 8745, 17490 and their sum is 46656 = 6^6. MAPLE with(numtheory): P:=proc(q) local a, k, n; for n from 1 to q do a:=sort([op(divisors(n))]); for k from 1 to nops(a) do if sigma(n)=a[k]^6 then print(n); break; fi; od; od; end: P(10^9); PROG (PARI) isok(n) = (n==1) || (ispower(s=sigma(n), 6) && !(n % sqrtnint(s, 6))); \\ Michel Marcus, May 05 2018 CROSSREFS Cf. A000203, A019424, A303123, A303993, A303994, A303995. Sequence in context: A043875 A236806 A048256 * A251641 A251638 A234562 Adjacent sequences: A303993 A303994 A303995 * A303997 A303998 A303999 KEYWORD nonn,easy AUTHOR Paolo P. Lava, May 04 2018 STATUS approved

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Last modified May 27 03:56 EDT 2024. Contains 372847 sequences. (Running on oeis4.)