login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A114099
Number of partitions of n into parts with digital root = 9.
13
1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 22, 0, 0, 0, 0, 0, 0, 0, 0, 30, 0, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0, 0, 56, 0, 0, 0
OFFSET
0,19
COMMENTS
a(n) = A114102(n) - A116371(n) - A116372(n) - A116373(n) - A116374(n) - A116375(n) - A116376(n) - A116377(n) - A116378(n).
LINKS
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