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A308421 Sums of two distinct refactorable numbers. 0
3, 9, 10, 11, 13, 14, 17, 19, 20, 21, 25, 26, 27, 30, 32, 33, 36, 37, 38, 41, 42, 44, 45, 48, 49, 52, 54, 57, 58, 60, 61, 62, 64, 65, 68, 69, 72, 73, 74, 76, 78, 80, 81, 82, 84, 85, 86, 88, 89, 90, 92, 93, 96, 97, 98, 100, 102, 104, 105, 106, 108, 109, 110 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..63.

Eric Weisstein's World of Mathematics, Refactorable Number

MATHEMATICA

Flatten[Table[If[Sum[ (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, 100}]]

CROSSREFS

Cf. A033950.

Sequence in context: A329560 A330296 A043048 * A309349 A024574 A119203

Adjacent sequences:  A308418 A308419 A308420 * A308422 A308423 A308424

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, Jul 24 2019

STATUS

approved

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Last modified October 22 23:18 EDT 2021. Contains 348180 sequences. (Running on oeis4.)