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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 (list; graph; refs; listen; history; text; internal format)
 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 Seiichi Manyama, Table of n, a(n) for n = 1..1000 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 Cf. A000367, A060976, A069040, A070192, A070193, A281662. Sequence in context: A049283 A141162 A160035 * A353154 A325962 A210451 Adjacent sequences: A281645 A281646 A281647 * A281649 A281650 A281651 KEYWORD nonn AUTHOR Seiichi Manyama, Jan 26 2017 STATUS approved

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Last modified March 31 05:21 EDT 2023. Contains 361634 sequences. (Running on oeis4.)