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 A216044 Numbers k such that Sum_{j=1..k-1} (4j)!/16^j is an integer. 5
 1, 3, 13, 15, 61, 106, 253, 27545, 62785, 218107, 1004593 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Next term > 1200000. LINKS Table of n, a(n) for n=1..11. MATHEMATICA seq={}; sum=0; fak=1; k=0; While[k<10000, sum+=fak; If[Denominator[sum]==1, AppendTo[seq, k+1]]; k++; fak*=k*(4*k-1)*(4*k-2)*(4*k-3)/4; ]; seq CROSSREFS Cf. A215972, A216042, A216043, A216045. Sequence in context: A152270 A032919 A340018 * A023144 A152269 A063674 Adjacent sequences: A216041 A216042 A216043 * A216045 A216046 A216047 KEYWORD nonn,more AUTHOR Vaclav Kotesovec, Aug 30 2012 STATUS approved

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Last modified September 27 07:30 EDT 2023. Contains 365674 sequences. (Running on oeis4.)