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 A080500 a(n) = (n-1)(n-4)(n-9)...(n-k^2) where k^2 < n <= (k+1)^2. 4
 1, 1, 2, 3, 4, 10, 18, 28, 40, 54, 140, 264, 432, 650, 924, 1260, 1664, 4284, 8100, 13376, 20400, 29484, 40964, 55200, 72576, 93500, 236808, 443232, 728000, 1108380, 1603800, 2235968, 3028992, 4009500, 5206760, 6652800, 8382528, 20867704 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The idea of A080497 to A080500 when applied to Euler's phi function i.e. on phi-torial function defined in A001783 yields A001783 itself for obvious reasons. Is there any other such example? LINKS EXAMPLE a(6) = (6-1)(6-4)= 10. CROSSREFS Cf. A080497, A080498, A072513. Sequence in context: A285190 A055506 A098088 * A007661 A049891 A135432 Adjacent sequences:  A080497 A080498 A080499 * A080501 A080502 A080503 KEYWORD nonn AUTHOR Amarnath Murthy, Mar 19 2003 EXTENSIONS More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003 STATUS approved

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Last modified August 16 15:19 EDT 2017. Contains 290624 sequences.