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A134608 Composite numbers such that the cube root of the sum of cubes of their prime factors is an integer. 20
256, 588, 693, 3840, 6561, 14157, 17787, 141960, 178360, 313600, 337365, 350000, 387072, 390625, 407442, 432000, 466560, 531674, 535815, 541310, 664909, 697851, 1044582, 1262056, 1264640, 1299272, 1374327, 1547570, 1608575, 1660360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Hieronymus Fischer, Table of n, a(n) for n = 1..300

EXAMPLE

a(3)=693, since 693=3*3*7*11 and (2*3^3+7^3+11^3)^(1/3)=1728^(1/3)=12.

PROG

(PARI) lista(m) = {for (i=2, m, if (! isprime(i), f = factor(i); s = sum (j=1, length(f~), f[j, 1]^3*f[j, 2]); if (ispower(s, 3), print1(i, ", ")); ); ); } \\ Michel Marcus, Apr 14 2013

CROSSREFS

Cf. A001597, A025475, A134333, A134344, A134376.

Cf. A134600, A134602, A134605, A134611, A134616, A134618, A134620.

Sequence in context: A206137 A206130 A110297 * A134609 A260065 A086061

Adjacent sequences:  A134605 A134606 A134607 * A134609 A134610 A134611

KEYWORD

nonn

AUTHOR

Hieronymus Fischer, Nov 11 2007

EXTENSIONS

Minor edits by Hieronymus Fischer, Apr 20 2013

STATUS

approved

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Last modified March 26 21:00 EDT 2017. Contains 284137 sequences.