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A186946 The smallest integer x > 0 such that the number of prime powers p^k (k>=1) in (x/2,x] equals n. 1
2, 3, 5, 9, 13, 25, 29, 31, 43, 49, 71, 73, 81, 103, 109, 113, 127, 131, 139, 157, 173, 181, 191, 193, 199, 239, 241, 269, 271, 283, 289, 293, 313, 349, 353, 361, 373, 379, 409, 419, 421, 433, 439, 443, 463, 499, 509, 523, 571, 577, 599, 601, 607, 613, 619 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

An analog of Labos primes (A080359) on prime powers>1 (A000961).

LINKS

Peter J. C. Moses, Table of n, a(n) for n = 1..10000

FORMULA

a(n) <= A186945(n).

MATHEMATICA

a000961Q[n_]:=(Length[FactorInteger[n]]==1) && IntegerQ[n]; nn=99; t=Table[0, {nn+1}]; s=0; Do[If[a000961Q[k], s++]; If[a000961Q[k/2], s--]; If[s<=nn && t[[s+1]]==0, t[[s+1]]=k], {k, 2, Prime[3*nn]}]; Prepend[Rest[t], 2] (* after T. D. Noe's code at A080359 *)(* Peter J. C. Moses, Sep 11 2013 *)

CROSSREFS

Cf. A080459, A186945, A228520, A228592.

Sequence in context: A228129 A175125 A171925 * A057225 A309289 A220315

Adjacent sequences: A186943 A186944 A186945 * A186947 A186948 A186949

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Aug 30 2013

EXTENSIONS

More terms from Peter J. C. Moses, Aug 30 2013

STATUS

approved

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Last modified February 5 22:19 EST 2023. Contains 360087 sequences. (Running on oeis4.)