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A250004 Numbers representable as x^y + x*y, where x>1, y>1 are integers (without multiplicity). 1
8, 14, 15, 24, 35, 36, 42, 48, 63, 76, 80, 93, 99, 120, 140, 142, 143, 168, 195, 224, 234, 255, 258, 272, 288, 323, 360, 364, 399, 440, 483, 528, 530, 536, 575, 624, 645, 675, 728, 747, 756, 783, 840, 899, 960, 1023, 1030, 1044, 1088, 1155, 1224, 1295, 1320, 1364, 1368 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence of numbers representable as x^y + x*y in two or more ways begins: 24, 76, 272, 1044, 2208, 4120, 16412. Example: 2208 = 46^2 + 46*2 = 3^7 + 3*7.

The subsequence of squares begins: 36, 1764.

LINKS

Table of n, a(n) for n=1..55.

EXAMPLE

a(2) = 14 = 2^3 + 2*3.

a(3) = 15 = 3^2 + 3*2.

a(22) = 255 = 15^2 + 15*2.

PROG

(PARI) isok(n) = {for (p=2, floor(log(n)/log(2)), for (k=2, sqrtnint(n, p), if (n == k^p + p*k, return (1)); ); ); return (0); } \\ Michel Marcus, Jan 16 2015

CROSSREFS

Cf. A253775.

Cf. A024036 is a subsequence, except first 2 terms.

Sequence in context: A219303 A082772 A103338 * A114456 A230422 A050681

Adjacent sequences:  A250001 A250002 A250003 * A250005 A250006 A250007

KEYWORD

nonn

AUTHOR

Alex Ratushnyak, Jan 14 2015

STATUS

approved

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Last modified December 9 03:27 EST 2019. Contains 329872 sequences. (Running on oeis4.)