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A137643
a(n) = ((2n)^((2n+1)^2) + 1)/(2n+1)^3.
1
1, 19, 9007199254741, 392750863685502459010271914701912679, 19389268200585836264288587113776883575610248525384021488302948711030121, 7513148009015777610818933132982719759579263711495116453794139744552967693463561232156273478587528174305033809166040571
OFFSET
0,2
FORMULA
a(n) = ((2n)^((2n+1)^2) + 1)/(2n+1)^3.
MATHEMATICA
Table[ ((2n)^((2n+1)^2) + 1)/(2n+1)^3, {n, 0, 10} ]
CROSSREFS
Cf. A137641 (((n-1)^(n^2) + 1)/n^3).
Cf. A137642 (((p+1)^(p^2) - 1)/p^3 where p = prime(n)).
Cf. A133591 (((p-1)^(p^2) + 1)/p^3 where p = prime(n)).
Sequence in context: A128400 A211378 A133591 * A351570 A023921 A072840
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Jan 31 2008
STATUS
approved