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 A069586 Smallest prime power p^k (k>=2) such that there is a difference of exactly n between p^k and some other prime power q^l (l >= 2); or 0 if no such q^l exists. 1
 8, 25, 125, 4, 4, 0, 9, 8, 16, 2187, 16, 4, 243, 0, 49, 9, 8, 9, 8, 0, 4, 27, 4, 8, 0, 0, 0, 4, 0, 6859, 0, 32, 16, 0, 0, 0, 27, 1331, 25, 9, 8, 0, 0, 81, 4, 243, 81, 16, 32, 0, 0, 0, 0, 27, 9, 8, 64, 0, 0, 4, 64, 0, 961, 64, 16, 0, 0, 0, 0, 0, 0, 9, 8, 169, 0, 49, 4, 0, 49, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Any solution for the terms that are currently zero is > 10^14. Since there are so many 'missing' values, I would recommend leaving the more keyword. - Larry Reeves (larryr(AT)acm.org), Jul 02 2002 LINKS EXAMPLE a(1) = 8 = 2^3 and 8+1 = 9=3^2; a(3) = 125 = 5^3 and 125 +3 =128 = 2^7. CROSSREFS First time a difference of n occurs in A025475 (with its initial 1 deleted). Sequence in context: A135942 A181207 A068315 * A253237 A275151 A302617 Adjacent sequences:  A069583 A069584 A069585 * A069587 A069588 A069589 KEYWORD nonn AUTHOR Amarnath Murthy, Mar 24 2002 EXTENSIONS More terms from Larry Reeves (larryr(AT)acm.org), Jul 02 2002 Description corrected by Karl W. Heuer, Apr 08 2012 STATUS approved

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Last modified December 7 13:08 EST 2021. Contains 349581 sequences. (Running on oeis4.)