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A083228
A Jacobsthal related sequence.
2
1, 3, 21, 341, 10923, 699051, 89478485, 22906492245, 11728124029611, 12009599006321323, 24595658764946068821, 100743818301219097892181, 825293359523586849932749483, 13521606402434446949298167524011
OFFSET
0,2
LINKS
FORMULA
a(n) = A001045(binomial(n+2, 2)) = 2^binomial(n+2, 2)/3 - (-1)^binomial(n+2, 2)/3.
PROG
(Magma) [2^Binomial(n+2, 2)/3-(-1)^Binomial(n+2, 2)/3: n in [0..15]]; // Vincenzo Librandi, Jun 29 2011
(PARI) a(n)=2^binomial(n+2, 2)\/3 \\ Charles R Greathouse IV, Jun 29 2011
CROSSREFS
Cf. A000217.
Sequence in context: A240936 A342245 A332928 * A376619 A052445 A351130
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 23 2003
STATUS
approved