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 A031218 Largest prime power <= n. 9
 1, 2, 3, 4, 5, 5, 7, 8, 9, 9, 11, 11, 13, 13, 13, 16, 17, 17, 19, 19, 19, 19, 23, 23, 25, 25, 27, 27, 29, 29, 31, 32, 32, 32, 32, 32, 37, 37, 37, 37, 41, 41, 43, 43, 43, 43, 47, 47, 49, 49, 49, 49, 53, 53, 53, 53, 53, 53, 59, 59, 61, 61, 61, 64, 64, 64, 67, 67, 67, 67, 71, 71 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 B. Dearden, J. Iiams, J. Metzger, Rumor Arrays, Journal of Integer Sequences, 16 (2013), #13.9.3. Eric Weisstein's World of Mathematics, Prime Power PROG (PARI) a(n)=if(n<1, 0, while(matsize(factor(n))[1]>1, n--); n) (Haskell) a031218 n = last \$ takeWhile (<= n) a000961_list -- Reinhard Zumkeller, Apr 25 2011 CROSSREFS Cf. A000015, A000961. Sequence in context: A073137 A131233 A136623 * A267508 A163382 A343127 Adjacent sequences:  A031215 A031216 A031217 * A031219 A031220 A031221 KEYWORD nonn,easy AUTHOR EXTENSIONS More terms from Erich Friedman. STATUS approved

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Last modified April 11 00:03 EDT 2021. Contains 342877 sequences. (Running on oeis4.)