A228151 Denominators of r(n) = r(n-1) + r(n-2) + B_(n-2), where B_n is the n-th Bernoulli number A027641(n)/A027642(n).
1, 1, 1, 2, 3, 6, 5, 30, 105, 70, 35, 70, 231, 2310, 143, 30030, 15015, 10010, 85085, 170170, 373065, 25194, 323323, 1939938, 22309287, 14872858, 168245, 74364290, 15935205, 223092870, 1078282205, 588153930, 20056049013, 5142576670, 393255863, 9550499530
Offset: 0
Programs
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Magma
t:=40; r:=[n le 2 select 0 else Self(n-1)+Self(n-2)+BernoulliNumber(n-3): n in [1..t]]; [n le 2 select 1 else Denominator(r[n]): n in [1..t]]; // Bruno Berselli, Sep 05 2013
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PARI
r(n) = if (n<=1, 0, r(n-1) + r(n-2) + bernfrac(n-2)); a(n) = if (n<=1, 1, denominator(r(n))); \\ Michel Marcus, Aug 24 2013
Extensions
More terms from Michel Marcus, Aug 24 2013
Comments