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A089607
a(n)=((-1)^(n+1)*A002425(n)) modulo 4.
1
1, 3, 1, 3, 3, 1, 1, 3, 3, 3, 1, 1, 3, 1, 1, 3, 3, 3, 1, 3, 3, 1, 1, 1, 3, 3, 1, 1, 3, 1, 1, 3, 3, 3, 1, 3, 3, 1, 1, 3, 3, 3, 1, 1, 3, 1, 1, 1, 3, 3, 1, 3, 3, 1, 1, 1, 3, 3, 1, 1, 3, 1, 1, 3, 3, 3, 1, 3, 3, 1, 1, 3, 3, 3, 1, 1, 3, 1, 1, 3, 3, 3, 1, 3, 3, 1, 1, 1, 3, 3, 1, 1, 3, 1, 1, 1, 3, 3, 1, 3, 3, 1, 1, 3, 3
OFFSET
1,2
FORMULA
a(1)=1; for n>=2, a(n) = 2*A014577(n-1)+1
PROG
(PARI) a(n)=numerator(2/n*(4^n-1)*bernfrac(2*n))%4
CROSSREFS
Cf. A056832.
Sequence in context: A122567 A122431 A279340 * A216637 A358643 A234308
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Dec 30 2003
STATUS
approved