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A226180
Denominators in Taylor series for integral of tan(x)/x.
1
1, 9, 75, 2205, 25515, 1715175, 79053975, 9577693125, 184530220875, 35266981624875, 4092826025413125, 66711917764366875, 92454016466921484375, 35047468562280596296875, 7641646200968365570359375, 3798425171964103092990703125, 133435000395771234460221796875
OFFSET
1,2
COMMENTS
Numerators are the same as those from the expansion of tan(x).
Unlike the "sine integral" function Si(x), it seems that there does not exist a "tan integral" function.
LINKS
FORMULA
A036279(n)*(2n-1).
MATHEMATICA
a[n_] := Denominator[(-1)^(n-1)*4^n*(4^n-1)*BernoulliB[2*n]/(2*n)!]*(2*n-1); Table[a[n], {n, 1, 17}]
CROSSREFS
Cf. A002430 (Numerators for tan(x)), A036279 (Denominators for tan(x)), A000367, A002445.
Sequence in context: A080254 A190916 A161736 * A274657 A255931 A319957
KEYWORD
nonn,frac
AUTHOR
STATUS
approved