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 A239521 Prime powers (A025475) such that the distance to the nearest prime power is an oblong number (A002378). 1
 25, 27, 2209, 3481, 3721, 6859, 6889, 18769, 22201, 22801, 157609, 1079521, 1630729, 1635841, 2621161, 2627641, 2825761, 3179089, 5257849, 5276209, 7447441, 7458361, 17032129, 17048641, 34304449, 34351321, 40436881, 40462321, 75290329, 75359761, 137288089, 137334961 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS PROG (PARI) lista(nn) = {precp = 1; currp = 4; for (nextp=5, nn, if (is_A025475(nextp), if (currp - precp < nextp - currp, tt = currp - precp, tt = nextp - currp); if (!(tt % 2) && ispolygonal(tt/2, 3), print1(currp, ", ")); precp = currp; currp = nextp; ); ); } \\ Michel Marcus, Apr 11 2014 CROSSREFS Cf. A002378, A025475, A239520 - A239523. Sequence in context: A015734 A221617 A083806 * A295748 A254226 A195613 Adjacent sequences:  A239518 A239519 A239520 * A239522 A239523 A239524 KEYWORD nonn AUTHOR Alex Ratushnyak, Mar 20 2014 STATUS approved

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Last modified April 3 14:34 EDT 2020. Contains 333197 sequences. (Running on oeis4.)