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A264744
Exponent of the prime power A264734(n).
1
1, 1, 1, 2, 1, 2, 3, 1, 4, 1, 1, 1, 1
OFFSET
1,4
COMMENTS
Subsequence of A025474.
EXAMPLE
a(9) = 4 is the exponent of 81 = A264734(9) = 3^4.
MATHEMATICA
t = Prepend[Select[Range@ 100000, AllTrue[{# - 2, #, # + 2}, PrimePowerQ] &], 3]; Flatten@ Map[Last, FactorInteger@ # &@ t, {2}] (* Michael De Vlieger, Dec 03 2015, Version 10 *)
PROG
(PARI) is(k) = isprimepower(k) || k==1;
for(k=1, 1e6, if(is(k) && is(k+2) && is(k-2), print1(bigomega(k), ", "))) \\ Altug Alkan, Nov 23 2015
CROSSREFS
Cf. A025474, A264734 (prime power k such that both k - 2 and k + 2 is a prime power).
Sequence in context: A283827 A122087 A139642 * A354322 A358532 A143604
KEYWORD
nonn,more,less
AUTHOR
STATUS
approved