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 A045974 If m = p_i^e_i, n=Prod p_j^f_j, set G_m(n) = Prod p_{j+i}^{f_j*e_i}; extend G_m to all m by multiplicativity; sequence gives a(n)=G_n(n). 1
 1, 3, 7, 81, 13, 525, 19, 19683, 2401, 1911, 29, 354375, 37, 6897, 11011, 43046721, 43, 4501875, 53, 2528253, 22477, 14703, 61, 2152828125, 28561, 32079, 40353607, 22532499, 71, 40465425, 79, 847288609443, 58667, 46569, 71383, 75969140625, 89 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS m is a prime power iff a(m) is a prime power: A010055(a(A000961(n))) = 1 and A010055(a(A024619(n))) = 0. [Reinhard Zumkeller, Feb 16 2012] REFERENCES From a puzzle proposed by Marc LeBrun. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 EXAMPLE G_2(6)=3*5, G_3(6)=5*7, so G_6(6)=3*5*5*7=525. PROG (Haskell) a045974 n = g n n where    g x y = product [a000040 (a049084 pi + a049084 pj) ^ (ei * ej) |                     (pi, ei) <- zip (a027748_row x) (a124010_row x),                     (pj, ej) <- zip (a027748_row y) (a124010_row y)] -- Reinhard Zumkeller, Feb 16 2012 CROSSREFS Cf. A027748, A124010, A049084, A000040. Sequence in context: A116294 A077793 A175236 * A001531 A219588 A219375 Adjacent sequences:  A045971 A045972 A045973 * A045975 A045976 A045977 KEYWORD nonn,nice,easy AUTHOR EXTENSIONS More terms from Naohiro Nomoto, Mar 14 2001 STATUS approved

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Last modified March 18 22:11 EDT 2019. Contains 321305 sequences. (Running on oeis4.)