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 A215976 2-adic valuation of the denominator of sum( k!/2^k, k=1..n ). 2
 1, 0, 2, 2, 0, 2, 3, 3, 3, 3, 2, 0, 3, 0, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 0, 3, 4, 4, 0, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 3, 2, 4, 0, 5, 5, 5, 5, 4, 0, 5, 0, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS By construction, this denominator is always a power of 2, the present sequence specifies which power. The sum is an integer iff a(n)=0, the corresponding n are listed in A215974 (= A215972 - 1). LINKS FORMULA denominator( sum( k!/2^k, k=1..n )) = 2^a(n). a(n)=0 <=> n is in A215974 <=> n+1 is in A215972. PROG (PARI) s=0; for(k=1, 199, print1(valuation(denominator(s+=k!/2^k), 2), ", ")) CROSSREFS The numerator of the sum is given in A215990. Sequence in context: A241533 A072738 A165316 * A141058 A102706 A105673 Adjacent sequences:  A215973 A215974 A215975 * A215977 A215978 A215979 KEYWORD nonn AUTHOR M. F. Hasler, Aug 29 2012 STATUS approved

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Last modified May 12 17:19 EDT 2021. Contains 343829 sequences. (Running on oeis4.)