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A111696
a(n) = C(n,a)+C(n,b)+C(n,c)... where n = abc... are the decimal digits of n.
3
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 22, 78, 299, 1015, 3018, 8024, 19465, 43776, 92397, 191, 231, 462, 2024, 10902, 53430, 230555, 888381, 3108483, 10015411, 4061, 4526, 5456, 10912, 52360, 331177, 1954932, 10303242, 48911928, 211924271, 91391, 101311
OFFSET
0,11
COMMENTS
a(10^n) = 10^n. a{(10^n-1)/9} = n*((10^n-1)/9).
a(0)=1 since C(0,0)=1.
EXAMPLE
a(12) = C(12,1)+C(12,2) = 12+66 = 78.
a(111) = 333.
MATHEMATICA
f[n_] := Plus @@ Binomial[n, IntegerDigits[n]]; Table[ f[n], {n, 41}] (* Robert G. Wilson v *)
CROSSREFS
Cf. A111695.
Sequence in context: A292926 A109687 A225361 * A047902 A081930 A143964
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Aug 17 2005
EXTENSIONS
Edited, corrected and extended by Robert G. Wilson v, Aug 19 2005
STATUS
approved