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 A104354 Euler's totient of A104350(n). 1
 1, 1, 2, 4, 16, 48, 288, 576, 1728, 8640, 86400, 259200, 3110400, 21772800, 108864000, 217728000, 3483648000, 10450944000, 188116992000, 940584960000, 6584094720000, 72425041920000, 1593350922240000, 4780052766720000, 23900263833600000, 310703429836800000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Amiram Eldar, Table of n, a(n) for n = 1..640 Reinhard Zumkeller, Products of largest prime factors of numbers <= n. FORMULA a(n) = A000010(A104350(n)). MATHEMATICA EulerPhi[FoldList[Times, Array[FactorInteger[#][[-1, 1]] &, 30]]] (* Amiram Eldar, Apr 08 2024 *) PROG (PARI) gpf(n) = my(f=factor(n)[, 1]); f[#f]; a(n) = eulerphi(prod(i=2, n, gpf(i))); \\ Michel Marcus, Nov 12 2023 CROSSREFS Cf. A000010, A048855, A104350. Sequence in context: A248748 A350646 A165905 * A153948 A284730 A255730 Adjacent sequences: A104351 A104352 A104353 * A104355 A104356 A104357 KEYWORD nonn,changed AUTHOR Reinhard Zumkeller, Mar 06 2005 EXTENSIONS a(1) prepended by Michel Marcus, Nov 12 2023 STATUS approved

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Last modified April 13 05:19 EDT 2024. Contains 371639 sequences. (Running on oeis4.)