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%I #4 Mar 30 2012 17:28:19
%S 10,36,84,126,126,84,36,9,1
%N Number of n-digit integers with decimal digits in increasing order.
%C There are precisely 512 such numbers, see A009993.
%F a(1)=1, at n>1: a(n)=binomial(10, n)(1 - n/10)
%e a(2)=36 because there are 36 two-digit integers whose decimal digits are in increasing order (see A009993): 12, 13, 14, 15, 16, 17, 18, 19, 23, 24, 25, 26, 27, 28, 29, 34, 35, 36, 37, 38, 39, 45, 46, 47, 48, 49, 56, 57, 58, 59, 67, 68, 69, 78, 79, 89
%Y Cf. A009993.
%K fini,full,nonn,base
%O 1,1
%A _Zak Seidov_, May 09 2006
%E Edited by _Charles R Greathouse IV_, Aug 05 2010
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