A116376 Number of partitions of n into parts with digital root = 6.
0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 1, 0, 0, 3, 0, 0, 2, 0, 0, 3, 0, 0, 3, 0, 0, 4, 0, 0, 4, 0, 0, 6, 0, 0, 5, 0, 0, 7, 0, 0, 7, 0, 0, 9, 0, 0, 9, 0, 0, 12, 0, 0, 11, 0, 0, 15, 0, 0, 15, 0, 0, 18, 0, 0, 19, 0, 0, 23, 0, 0, 23, 0, 0, 29, 0, 0, 29, 0, 0, 35, 0, 0, 37
Offset: 1
Examples
a(30) = #{24+6, 15+15, 6+6+6+6+6} = 3.
Links
- Eric Weisstein's World of Mathematics, Digital Root
Programs
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Maple
N:= 1000: # to get a(1) to a(N) g:= mul(1/(1-x^(6+9*j)), j=0..floor((N-6)/9)): S:= series(g, x, N+1): seq(coeff(S,x,j),j=1..N); # Robert Israel, Apr 13 2015
Formula
a(n) = A035386(floor(n/3))*0^(n mod 3).
G.f.: Product_{j>=0} 1/(1 - x^(6+9*j)). - Robert Israel, Apr 13 2015
Comments