A089607 a(n)=((-1)^(n+1)*A002425(n)) modulo 4.

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

Author

Benoit Cloitre, Dec 30 2003

Keywords

• nonn

Crossrefs

Cf. A056832.

Programs

PARI

a(n)=numerator(2/n*(4^n-1)*bernfrac(2*n))%4

Formula

a(1)=1; for n>=2, a(n) = 2*A014577(n-1)+1