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 A131908 Smallest positive integer k with the same sum of cubes of divisors as the n-th integer for which such a k exists. 9
 184926, 291741, 583482, 1166964, 1458705, 1880574, 2042187, 2333928, 2404038, 2917410, 3209151, 3513594, 3792633, 4084374, 4253298, 4667856, 4959597, 5543079, 5362854, 5834820, 5732706, 6418302, 6710043, 7293525, 7585266 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..25. Max Alekseyev, List of first 224 pairs A131907(n), A131908(n) FORMULA a(n)=min(k>0, k has the same sum of cubes of divisors as A131907(n)) EXAMPLE a(1)=184926 because A131907(1)=194315 with the sum of cubes of its divisors being 7401260364550416. This is the same as the sum of cubes of divisors of 184926 and there is no positive integer less than 184926 with this cubesum of its divisors MATHEMATICA Last@Transpose[Reap[For[n = 1, n <= 5*10^6, n++, (If[Head[ #1] === tmp, #1 = n, Sow[{n, #1}]] & )[ tmp[DivisorSigma[3, n]]]]][[2, 1]]] CROSSREFS Cf. A069822, A131902-A131907. Sequence in context: A244173 A245795 A251449 * A234409 A254772 A254779 Adjacent sequences: A131905 A131906 A131907 * A131909 A131910 A131911 KEYWORD nonn AUTHOR Peter Pein (petsie(AT)dordos.net), Jul 26 2007, Jul 28 2007 EXTENSIONS More terms from Max Alekseyev, Jul 28 2007 STATUS approved

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Last modified April 13 15:24 EDT 2024. Contains 371644 sequences. (Running on oeis4.)