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A165938
a(n) = A002203(n^2) for n>=1.
4
2, 34, 2786, 1331714, 3710155682, 60245508192802, 5701755387019728962, 3145168096065837266706434, 10111847525912679844192131854786, 189482250299273866835746159841800035874, 20694642381734231604510939638726181796865594402
OFFSET
1,1
LINKS
FORMULA
a(n) == 2 (mod 32).
a(n) = (1+sqrt(2))^(n^2) + (1-sqrt(2))^(n^2).
Logarithmic derivative of A165937.
MATHEMATICA
Simplify[Table[(1 + Sqrt[2])^(n^2) + (1 - Sqrt[2])^(n^2), {n, 1, 7}]] (* G. C. Greubel, Apr 18 2016 *)
PROG
(PARI) {a(n)=polcoeff(2*(1-x)/(1-2*x-x^2 +x*O(x^(n^2))), n^2)}
CROSSREFS
Cf. A165937, A002203, A000129 (Pell numbers).
Sequence in context: A198909 A207865 A216082 * A255434 A206501 A183414
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Oct 18 2009
STATUS
approved