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A195942 Zeroless prime powers (excluding primes): Intersection of A025475 and A052382. 21
1, 4, 8, 9, 16, 25, 27, 32, 49, 64, 81, 121, 125, 128, 169, 243, 256, 289, 343, 361, 512, 529, 625, 729, 841, 961, 1331, 1369, 1681, 1849, 2187, 2197, 3125, 3481, 3721, 4489, 4913, 5329, 6241, 6561, 6859, 6889, 7921, 8192 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Reinhard Zumkeller and T. D. Noe, Table of n, a(n) for n = 1..4094 (terms < 10^10)

C. Rivera, Puzzle 607. A zeroless Prime power, on primepuzzles.net, Sept. 24, 2011.

FORMULA

A195942 = A025475 intersect A052382.

A010055(a(n)) * (1 - A010051(a(n))) * A168046(a(n)) = 1. - Reinhard Zumkeller, Sep 27 2011

MATHEMATICA

mx = 10^10; t = {1}; p = 2; While[pw = 2; While[n = p^pw; n <= mx, If[Union[IntegerDigits[n]][[1]] > 0, AppendTo[t, n]]; pw++]; pw > 2, p = NextPrime[p]]; t = Sort[t] (* T. D. Noe, Sep 27 2011 *)

PROG

(PARI) for( n=1, 9999, is_A025475(n) && is_A052382(n) && print1(n", "))

(Haskell)

a195942 n = a195942_list !! (n-1)

a195942_list = filter (\x -> a010051 x == 0 && a010055 x == 1) a052382_list

-- Reinhard Zumkeller, Sep 27 2011

CROSSREFS

Cf. A195985, A195943, A195944, A195945, A195946, A195908, A195948, A007377, A008839, A030700, A030701, A030702, A030703, A030704, A030705, A030706.

Sequence in context: A134612 A025475 A246547 * A125643 A002760 A115651

Adjacent sequences:  A195939 A195940 A195941 * A195943 A195944 A195945

KEYWORD

nonn,base,easy

AUTHOR

M. F. Hasler, Sep 25 2011

STATUS

approved

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Last modified July 18 11:30 EDT 2019. Contains 325138 sequences. (Running on oeis4.)