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A051848
Bisection of A023811, divided by the term position.
0
1, 9, 373, 48913, 13717421, 6698798233, 5057809205989, 5465701947765793, 8008631808527689309, 15287592943577781017641, 36867279706750843040346261, 109619115381793714510485861169, 393991653133258067890987154457613, 1683967033137904529927995135566966713
OFFSET
1,2
FORMULA
a(n) = A023811(2n)/(2n-1). [Corrected by Alexander R. Povolotsky, Oct 15 2022]
a(n) = A221741(2n-1). - Alexander R. Povolotsky, Oct 15 2022
PROG
(PARI) f(n) = (n^n-n^2)\(n-1)^2+1; \\ A023811
a(n) = f(2*n)/(2*n-1); \\ Michel Marcus, Oct 16 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Antti Karttunen, Dec 13 1999
EXTENSIONS
a(13) and a(14) added by Alexander R. Povolotsky, Oct 16 2022
STATUS
approved