id:A161178 - OEIS Search Results

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Sum of double factorials of the digits of n.

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1, 1, 2, 3, 8, 15, 48, 105, 384, 945, 2, 2, 3, 4, 9, 16, 49, 106, 385, 946, 3, 3, 4, 5, 10, 17, 50, 107, 386, 947, 4, 4, 5, 6, 11, 18, 51, 108, 387, 948, 9, 9, 10, 11, 16, 23, 56, 113, 392, 953, 16, 16, 17, 18, 23, 30, 63, 120, 399, 960, 49, 49, 50, 51, 56, 63, 96, 153, 432, 993 (list; graph; listen)

	OFFSET	`0,3`
	EXAMPLE	`a(24) = (2!!) + (4!!) = 2 + 8 = 10. a(35) = (3!!) + (5!!) = 3 + 15 = 18.`
	MAPLE	`P:=proc(i) local a, b, c, n; print(1); for n from 1 by 1 to i do a:=0; b:=n; while b>0 do c:=10*frac(b/10); a:=a+doublefactorial(c); b:=trunc(b/10); od; print(a); od; end: P(100);`
	CROSSREFS	`A061602` `Sequence in context: A148010 A148011 A148012 this_sequence A006882 A080498 A148013` `Adjacent sequences: A161175 A161176 A161177 this_sequence A161179 A161180 A161181`
	KEYWORD	`easy,nonn,uned`
	AUTHOR	`Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Jun 05 2009`

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.

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