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A171607 Expressible as A*B^A in a nontrivial way. 4
8, 18, 24, 32, 50, 64, 72, 81, 98, 128, 160, 162, 192, 200, 242, 288, 324, 338, 375, 384, 392, 450, 512, 578, 648, 722, 800, 882, 896, 968, 1024, 1029, 1058, 1152, 1215, 1250, 1352, 1458, 1536, 1568, 1682, 1800, 1922, 2048, 2178, 2187, 2312, 2450, 2500, 2592 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

R. Munafo, Generalized Cullen and Woodall Numbers

FORMULA

a(n) = 2n^2 - O(n^(5/3)). - Charles R Greathouse IV, Feb 19 2017

EXAMPLE

8=2*2^2. 24=3*2^3. 375=3*5^3.

PROG

(PARI) is(n)=if(n<8, return(0)); for(a=2, logint(n\2, 2), if(n%a==0 && ispower(n/a, a), return(1))); 0 \\ Charles R Greathouse IV, Feb 19 2017

(PARI) list(lim)=my(v=List()); if(lim<8, return([])); for(a=2, logint(lim\2, 2), for(b=2, sqrtnint(lim\a, a), listput(v, a*b^a))); Set(v) \\ Charles R Greathouse IV, Feb 19 2017

CROSSREFS

Cf. A171606. Union of the "KN^K" sequences A001105, A117642, A141046, ... or of the "NK^N" sequences A036289, A036290, A018215, A036291, ... but omitting the trivial initial terms.

Sequence in context: A051810 A034055 A043101 * A039278 A045043 A043881

Adjacent sequences:  A171604 A171605 A171606 * A171608 A171609 A171610

KEYWORD

nonn

AUTHOR

Robert Munafo, Dec 12 2009

STATUS

approved

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Last modified September 22 19:01 EDT 2018. Contains 315270 sequences. (Running on oeis4.)