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%I #23 Dec 12 2018 03:16:36
%S 1,30,210,330,2310,3990,6090,14790,43890,66990,82110,125970,144210,
%T 181830,881790,1009470,1067430,1217370,2284590,2381190,17687670,
%U 18888870,26265030,35068110,39544890,47763870,115223790,127652070,406816410,497668710,741110370,1024748670
%N Numbers that appear in A195441 at least once for two consecutive indices.
%C The sequence is infinite; see Cor. 3 in "The denominators of power sums of arithmetic progressions". - Bernd C. Kellner and _Jonathan Sondow_, May 24 2017
%H Bernd C. Kellner, On a product of certain primes, J. Number Theory, 179 (2017), 126-141. DOI:<a href="https://doi.org/10.1016/j.jnt.2017.03.020">10.1016/j.jnt.2017.03.020</a>, arXiv:<a href="https://arxiv.org/abs/1705.04303">1705.04303</a>.
%H Bernd C. Kellner and Jonathan Sondow, Power-Sum Denominators, Amer. Math. Monthly, 124 (2017), 695-709. DOI:<a href="https://doi.org/10.4169/amer.math.monthly.124.8.695">10.4169/amer.math.monthly.124.8.695</a>, arXiv:<a href="https://arxiv.org/abs/1705.03857">1705.03857</a>.
%H Bernd C. Kellner and Jonathan Sondow, The denominators of power sums of arithmetic progressions, Integers 18 (2018), Article A95, 1-17. Journal:<a href="https://www.integers-ejcnt.org/vol18.html">Integers 18</a>, arXiv:<a href="https://arxiv.org/abs/1705.05331">1705.05331</a>.
%e A195441(21) = A195441(22) = 30, so 30 is in the sequence. - _Jonathan Sondow_, Dec 11 2018
%t Take[#, 32] &@ Union@ SequenceCases[ Table[ Denominator[ Together[ (BernoulliB[n + 1, x] - BernoulliB[n + 1])]], {n, 0, 2000}], w_ /; And[SameQ @@ w, Length@ w >= 2]][[All, 1]] (* _Michael De Vlieger_, Sep 22 2017, after _Jonathan Sondow_ at A195441 *)
%o (Julia)
%o function A286763_search()
%o A = fmpz[]; a = fmpz(0)
%o for n in 0:10000
%o u = A195441(n)
%o a == u && push!(A, a)
%o a = u
%o end
%o S = sort([a for a in Set(A)])
%o S[1:32] end
%o println(A286763_search())
%Y Cf. A195441, A286516, A286762.
%K nonn
%O 1,2
%A _Peter Luschny_, May 14 2017
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