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A138363
Number of prime powers p^e with e>1 and 0<prime(n)-p^e<p.
3
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
OFFSET
1,10
COMMENTS
a(A049084(A074267(n))) > 0;
a(31)=2, what is the next value greater than 1?.
LINKS
EXAMPLE
A000040(10)=29: a(10) = #{4+5^2, 2+3^3} = 2.
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]
CROSSREFS
Sequence in context: A319532 A317576 A070205 * A080225 A122841 A326075
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 16 2008
STATUS
approved