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A289381
a(n) = numerator of Sum_{k=1..n} 1/(2*k-1)!!.
4
1, 4, 7, 148, 1333, 4888, 190633, 2859496, 1246447, 923617228, 19395961789, 11438644132, 1013879820791, 301122306774928, 171226409734763, 270708953790660304, 525493851475987649, 104222947209404217052, 11568747140243868092773, 451181138469510855618148
OFFSET
1,2
FORMULA
Numerators of coefficients in expansion of sqrt(Pi*x*exp(x)/2) * erf(sqrt(x/2)) / (1 - x). - Ilya Gutkovskiy, May 24 2022
EXAMPLE
1, 4/3, 7/5, 148/105, 1333/945, 4888/3465, 190633/135135, 2859496/2027025, 1246447/883575, 923617228/654729075, 19395961789/13749310575, 11438644132/8108567775, ... = a(n)/A289488(n) -> A060196.
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Seiichi Manyama, Sep 02 2017
STATUS
approved