

A309351


Sums of two distinct refactorable numbers whose product and difference are refactorable.


0



3, 10, 17, 36, 60, 84, 88, 96, 104, 108, 132, 136, 144, 152, 156, 168, 180, 184, 192, 204, 208, 216, 228, 232, 240, 248, 252, 264, 276, 288, 296, 300, 312, 324, 328, 336, 344, 348, 352, 372, 376, 384, 392, 396, 400, 408, 420, 424, 444, 456, 459, 468, 472
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..53.
Eric Weisstein's World of Mathematics, Refactorable Number


MATHEMATICA

Flatten[Table[If[Sum[ (1  Ceiling[(n  2 i)/DivisorSigma[0, n  2 i]] + Floor[(n  2 i)/DivisorSigma[0, n  2 i]]) (1  Ceiling[(i (n  i))/DivisorSigma[0, i (n  i)]] + Floor[(i (n  i))/DivisorSigma[0, i (n  i)]]) (1  Ceiling[i/DivisorSigma[0, i]] + Floor[i/DivisorSigma[0, i]]) (1  Ceiling[(n  i)/DivisorSigma[0, n  i]] + Floor[(n  i)/DivisorSigma[0, n  i]]), {i, Floor[(n  1)/2]}] > 0, n, {}], {n, 500}]]


CROSSREFS

Cf. A033950.
Sequence in context: A309347 A273235 A334964 * A003615 A043293 A208894
Adjacent sequences: A309348 A309349 A309350 * A309352 A309353 A309354


KEYWORD

nonn


AUTHOR

Wesley Ivan Hurt, Jul 24 2019


STATUS

approved



