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A138363
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Number of prime powers p^e with e>1 and 0<prime(n)-p^e<p.
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3
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0, 0, 1, 0, 1, 0, 1, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 2, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,10
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COMMENTS
| a(A049084(A074267(n))) > 0;
a(31)=2, what is the next value greater than 1?.
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LINKS
| R. Zumkeller, Table of n, a(n) for n = 1..10000
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EXAMPLE
| A000040(10)=29: a(10) = #{4+5^2, 2+3^3} = 2.
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MATHEMATICA
| f[n_] := Block[{c = 0, j, k = 1, p = Prime@ n, q}, j = 1 + PrimePi@ Sqrt@ p; While[k < j, q = Prime@ k; If[p < q + q^Floor@ Log[q, p], c++ ]; k++ ]; c]; Array[f, 105]
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CROSSREFS
| Sequence in context: A053201 A028605 A070205 * A080225 A122841 A060862
Adjacent sequences: A138360 A138361 A138362 * A138364 A138365 A138366
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 16 2008
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