A281662 (Denominator of Bernoulli(2*n)) read mod n.
0, 0, 0, 2, 1, 0, 6, 6, 6, 0, 6, 6, 6, 2, 12, 14, 6, 12, 6, 10, 0, 8, 6, 18, 16, 4, 15, 2, 6, 0, 6, 30, 9, 30, 31, 30, 6, 30, 3, 10, 6, 0, 6, 30, 3, 30, 6, 42, 6, 30, 42, 30, 6, 30, 33, 6, 42, 30, 6, 30, 6, 30, 42, 62, 1, 24, 6, 30, 42, 50, 6, 6, 6, 30, 72, 30, 61
Offset: 1
Keywords
Links
- Seiichi Manyama, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
f[n_] := Mod[Denominator[BernoulliB[2 n]], n]; Array[f, 77] (* Robert G. Wilson v, Jan 26 2017 *)
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PARI
a(n) = denominator(bernfrac(2*n)) % n; \\ Michel Marcus, Jan 29 2017
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Ruby
def bernoulli(n) ary = [] a = [] (0..n).each{|i| a << 1r / (i + 1) i.downto(1){|j| a[j - 1] = j * (a[j - 1] - a[j])} ary << a[0] } ary end def A281662(n) a = bernoulli(2 * n) (1..n).map{|i| a[2 * i].denominator % i} end
Formula
a(n) = A002445(n) mod n.
Comments