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 A061603 a(n) = n! / {product of factorials of the digits of n}. 2
 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3628800, 39916800, 239500800, 1037836800, 3632428800, 10897286400, 29059430400, 70572902400, 158789030400, 335221286400, 1216451004088320000, 25545471085854720000, 281000181944401920000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,11 COMMENTS It can be shown that the terms obtained by the above formula are positive integers using the fact that k! divides a product of k consecutive numbers. LINKS Harry J. Smith, Table of n, a(n) for n = 0..100 FORMULA a(n) = A000142(n)/A066459(n). - Michel Marcus, Jul 02 2018 EXAMPLE a(12) = (12!) / { (1!)(2!) = 239500800. MATHEMATICA Table[n!/Times@@(IntegerDigits[n]!), {n, 0, 30}] (* Harvey P. Dale, Jan 19 2017 *) PROG (PARI) { for (n=0, 100, p=1; x=n; until (x==0, p*=(x - 10*(x\10))!; x\=10); write("b061603.txt", n, " ", n!/p) ) } \\ Harry J. Smith, Jul 25 2009 (PARI) a(n) = my(d = digits(n)); n!/prod(k=1, #d, d[k]!); \\ Michel Marcus, Jul 02 2018 CROSSREFS Cf. A000142, A061602, A066459. Sequence in context: A321846 A226889 A284207 * A153761 A133132 A228913 Adjacent sequences: A061600 A061601 A061602 * A061604 A061605 A061606 KEYWORD nonn,base,easy AUTHOR Amarnath Murthy, May 19 2001 EXTENSIONS Corrected and extended by Vladeta Jovovic, May 19 2001 STATUS approved

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Last modified December 7 00:23 EST 2023. Contains 367616 sequences. (Running on oeis4.)