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A086894 a(n) = (A000522(2*n) + 1)/2. 1
1, 3, 33, 979, 54801, 4932051, 651030673, 118487582403, 28437019776609, 8701728051642211, 3306656659624040001, 1527675376746306480243, 843276807963961177093873, 548129925176574765111017139, 414386223433490522423928956721, 360516014387136754508818192346851 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
a(n) = (1 + (2*n)!*Sum_{k=0..2*n} 1/k!)/2. - Andrew Howroyd, Jan 05 2020
PROG
(PARI) a(n)={(1 + sum(k=0, 2*n, (2*n)!/k!))/2} \\ Andrew Howroyd, Jan 05 2020
CROSSREFS
Cf. A000522.
Sequence in context: A126466 A002112 A055549 * A255930 A255883 A215948
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Aug 22 2003
EXTENSIONS
Terms a(11) and beyond from Andrew Howroyd, Jan 05 2020
STATUS
approved

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Last modified March 28 10:55 EDT 2024. Contains 371241 sequences. (Running on oeis4.)