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A281648
(Numerator of Bernoulli(2*n)) read mod n.
2
0, 1, 1, 3, 0, 5, 0, 7, 1, 9, 0, 5, 0, 7, 5, 15, 0, 11, 0, 9, 1, 11, 0, 13, 0, 13, 19, 7, 0, 19, 0, 31, 11, 17, 0, 11, 0, 19, 13, 13, 0, 37, 0, 33, 35, 23, 0, 37, 0, 39, 34, 39, 0, 11, 5, 35, 19, 29, 0, 29, 0, 31, 61, 63, 0, 55, 0, 51, 23, 21, 0, 43, 0, 37, 50, 19
OFFSET
1,4
COMMENTS
Conjecture: a(n) == n-1 (mod n) if only if n = 6, 10 or n = 2^k for k >= 0. This is true for n <= 1024. - Seiichi Manyama, Jan 27 2017
LINKS
FORMULA
a(n) = A000367(n) mod n.
MATHEMATICA
f[n_] := Mod[Numerator[BernoulliB[2 n]], n]; Array[f, 77] (* Robert G. Wilson v, Jan 26 2017 *)
PROG
(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 A281648(n)
a = bernoulli(2 * n)
(1..n).map{|i| a[2 * i].numerator % i}
end
(PARI) a(n)=numerator(bernfrac(2*n))%n \\ Charles R Greathouse IV, Jan 27 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jan 26 2017
STATUS
approved