A064450 Sum of totients of binomial coefficients C(n,j), j=0..n.
1, 2, 3, 6, 8, 18, 30, 86, 106, 158, 290, 662, 1410, 3674, 7166, 16242, 20242, 46754, 72910, 162686, 304866, 524570, 1179430, 2842710, 5230210, 11035402, 24478394, 40473686, 63927602, 155016682, 328928338, 888801182, 928681474, 1765045802
Offset: 0
Keywords
Examples
For n=4, the binomial coefficients C(4,j) are 1, 4, 6, 4, and 1. The totients are 1, 2, 2, 2, and 1. So a(4) = 1 + 2 + 2 + 2 + 1 = 8. - _Michael B. Porter_, Jun 25 2018
Links
- Harry J. Smith, Table of n, a(n) for n = 0..200
Programs
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Mathematica
a(n)=Apply[Plus, Table[EulerPhi[Binomial[n, w]], {w, 0, n}]], -
PARI
a(n) = vecsum(vector(n+1, k, eulerphi(binomial(n, k-1)))); \\ Michel Marcus, Jun 24 2018
Comments