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A246550 Prime powers p^e where p is a prime and e >= 4. 2
16, 32, 64, 81, 128, 243, 256, 512, 625, 729, 1024, 2048, 2187, 2401, 3125, 4096, 6561, 8192, 14641, 15625, 16384, 16807, 19683, 28561, 32768, 59049, 65536, 78125, 83521, 117649, 130321, 131072, 161051, 177147, 262144, 279841, 371293, 390625, 524288, 531441, 707281, 823543, 923521, 1048576, 1419857, 1594323, 1771561 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

FORMULA

Sum_{n>=1} 1/a(n) = Sum_{p prime} 1/(p^3*(p-1)) = 0.1461466097... - Amiram Eldar, Oct 24 2020

MAPLE

N:= 10^7: # to get all terms <= N

{seq(seq(p^m, m=4..floor(log[p](N))), p = select(isprime, [2, seq(2*i+1, i=1..floor(N^(1/4)))]))}; # Robert Israel, Aug 29 2014

MATHEMATICA

With[{max = 10^6}, Sort @ Flatten @ Table[p^Range[4, Floor[Log[p, max]]], {p, Select[Range[Surd[max, 4]], PrimeQ]}]] (* Amiram Eldar, Oct 24 2020 *)

PROG

(PARI) m=10^7; v=[]; forprime(p=2, m^(1/4), e=4; while(p^e<=m, v=concat(v, p^e); e++)); v=vecsort(v) \\ Jens Kruse Andersen, Aug 29 2014

CROSSREFS

Cf. A000961, A246547, A246549, A168363.

Sequence in context: A172418 A036967 A076468 * A197917 A317475 A335161

Adjacent sequences:  A246547 A246548 A246549 * A246551 A246552 A246553

KEYWORD

nonn

AUTHOR

Joerg Arndt, Aug 29 2014

STATUS

approved

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Last modified April 12 00:32 EDT 2021. Contains 342912 sequences. (Running on oeis4.)