A113046 Diagonal sums of number triangle binomial(n, floor((n-k)/2)) mod 3.
1, 1, 3, 1, 1, 3, 5, 5, 6, 3, 3, 3, 3, 3, 3, 1, 1, 9, 11, 11, 12, 5, 5, 15, 16, 10, 12, 6, 6, 9, 9, 6, 6, 3, 3, 9, 9, 9, 9, 3, 3, 9, 9, 6, 6, 3, 3, 3, 3, 3, 3, 1, 1, 27, 29, 29, 30, 11, 11, 33, 34, 22, 24, 12, 12, 15, 15, 12, 12, 5, 5, 45, 46, 28, 30, 16, 16, 30, 32, 23, 24, 12, 12, 18, 18, 12
Offset: 0
Links
- Antti Karttunen, Table of n, a(n) for n = 0..10000
Crossrefs
Cf. A113045.
Programs
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Maple
A113046:=n->add(binomial(n-k, floor((n-2*k)/2)) mod 3, k=0..floor(n/2)): seq(A113046(n), n=0..150); # Wesley Ivan Hurt, Jul 25 2017
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PARI
A113046(n) = sum(k=0,n\2,binomial(n-k,((n-(2*k))\2))%3); \\ Antti Karttunen, Jul 24 2017
Formula
a(n) = Sum_{k=0..floor(n/2)} binomial(n-k, floor((n-2k)/2)) mod 3.
Comments