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A131605 Perfect powers of nonprimes (m^k where m is a nonprime positive integer and k >= 2). 5
1, 36, 100, 144, 196, 216, 225, 324, 400, 441, 484, 576, 676, 784, 900, 1000, 1089, 1156, 1225, 1296, 1444, 1521, 1600, 1728, 1764, 1936, 2025, 2116, 2304, 2500, 2601, 2704, 2744, 2916, 3025, 3136, 3249, 3364, 3375, 3600, 3844, 3969, 4225, 4356, 4624 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Although 1 is a square, is a cube, and so on..., 1 is sometimes excluded from perfect powers since it is not a well-defined power of 1 (1 = 1^k for any k in [2, 3, 4, 5, ...])

LINKS

Daniel Forgues, Table of n, a(n) for n=1..8649

PROG

(PARI) isok(n) = if (n == 1, return (1), return (ispower(n, , &np) && (! isprime(np)))); \\ Michel Marcus, Jun 12 2013

CROSSREFS

Cf. A000961, A001597, A024619, A025475.

Sequence in context: A137945 A250812 A072413 * A296204 A063734 A069057

Adjacent sequences:  A131602 A131603 A131604 * A131606 A131607 A131608

KEYWORD

nonn

AUTHOR

Daniel Forgues, May 27 2008

EXTENSIONS

Klaus Brockhaus previously provided a table of n, a(n) for n=1..1323, May 28 2008

STATUS

approved

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Last modified May 18 18:45 EDT 2021. Contains 343999 sequences. (Running on oeis4.)