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 A002021 Pile of coconuts problem: (n-1)(n^n - 1), n even; n^n - n + 1, n odd. (Formerly M3114 N1262) 5
 1, 3, 25, 765, 3121, 233275, 823537, 117440505, 387420481, 89999999991, 285311670601, 98077104930805, 302875106592241, 144456088732254195, 437893890380859361, 276701161105643274225, 827240261886336764161, 668888937280041138782191, 1978419655660313589123961 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS T. D. Noe, Table of n, a(n) for n = 1..100 Santo D'Agostino, “The Coconut Problem”; Updated With Solution, May 2011. R. S. Underwood and Robert E. Moritz, Problem 3242, Amer. Math. Monthly, 35 (1928), 47-48. Ben Ames Williams, Coconuts Problem R. G. Wilson, V, Letter to N. J. A. Sloane, Oct. 1993 FORMULA E.g.f.: (1-x)*exp(x)-(W(x)+2)*(2*W(x)+1)/(2*(1+W(x))^3)-W(-x)/(2*(1+W(-x))^3) where W is the Lambert W function. - Robert Israel, Aug 26 2016 MAPLE seq(`if`(n::even, (n-1)*(n^n - 1), n^n-n+1), n=1..30); # Robert Israel, Aug 26 2016 MATHEMATICA Table[If[EvenQ[n], (n-1)(n^n-1), n^n-n+1], {n, 30}] (* Harvey P. Dale, Apr 21 2012 *) CROSSREFS Cf. A002022, A006091. Sequence in context: A127231 A062411 A136516 * A012764 A219275 A101733 Adjacent sequences:  A002018 A002019 A002020 * A002022 A002023 A002024 KEYWORD easy,nonn,nice,changed AUTHOR EXTENSIONS More terms from Harvey P. Dale, Apr 21 2012 STATUS approved

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