OFFSET
1,2
COMMENTS
The 10-digit numbers distributed according to the sum of their digits n.
The sequence is symmetrical; a(n) = a(91 - n), 1 <= n <= 91.
LINKS
Miquel Cerda, Table of n, a(n) for n = 1..90
FORMULA
G.f.: (1 - x^10)^9*(x - x^10)/(1 - x)^10.
EXAMPLE
a(2)=10: 1000000001, 1000000010, 1000000100, 1000001000, 1000010000, 1000100000, 1001000000, 1010000000, 110000000, 200000000.
MATHEMATICA
CoefficientList[Series[(1 - x^10)^9*(1 - x^9)/(1 - x)^10, {x, 0, 40}],
x] (* Wesley Ivan Hurt, Jul 09 2017 *)
CROSSREFS
KEYWORD
base,fini,full,nonn
AUTHOR
Miquel Cerda, Jul 04 2017
STATUS
approved