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Sum of the double factorials of the digits of n.
1

%I #10 Aug 28 2013 15:26:49

%S 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,

%T 17,50,107,386,947,4,4,5,6,11,18,51,108,387,948,9,9,10,11,16,23,56,

%U 113,392,953,16,16,17,18,23,30,63,120,399,960,49,49,50,51,56,63,96,153,432,993

%N Sum of the double factorials of the digits of n.

%H Harvey P. Dale, <a href="/A161178/b161178.txt">Table of n, a(n) for n = 0..1000</a>

%e a(24) = (2!!) + (4!!) = 2 + 8 = 10. a(35) = (3!!) + (5!!) = 3 + 15 = 18.

%p A161178 := proc(n) if n = 0 then 1; else add(doublefactorial(d),d=convert(n,base,10)) ; end if; end proc:

%t Total[IntegerDigits[#]!!]&/@Range[0,70] (* _Harvey P. Dale_, Aug 28 2013 *)

%Y Cf. A061602, A006882.

%K easy,nonn,base

%O 0,3

%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Jun 05 2009