OFFSET
0,19
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..19683
Eric Weisstein's World of Mathematics, Digital Root
FORMULA
a(n) = A000041(floor(n/9))*0^(n mod 9).
a(9n) = A000041(n) and for all others a(n) = 0. [Robert G. Wilson v, Apr 25 2010]
EXAMPLE
a(27) = #{27, 18+9, 9+9+9} = 3.
MATHEMATICA
f[n_] := PartitionsP[n/9] If[Mod[n, 9] == 0, 1, 0]; Array[f, 105] (* Robert G. Wilson v, Apr 25 2010 *)
PROG
(PARI) A114099(n) = if((n%9), 0, numbpart(n/9)); \\ Antti Karttunen, Jul 22 2018
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Feb 12 2006
STATUS
approved