0,3

3^n=a(n)+3*A091001(n)+6*A091002(n)

G.f.: (1-2x-2x^2)((1-x)(1+2x)(1-3x)); a(n)=3^n/10+2(-2)^n/5+1/2.

a(n)=(A000244(n)+9*A001045(n+1)(-1)^n+6*A001045(n)(-1)^(n+1))/10.

Sequence in context: A130637 A054882 A086479 this_sequence A013490 A013351 A013407

Adjacent sequences: A090997 A090998 A090999 this_sequence A091001 A091002 A091003

easy,nonn

Paul Barry (pbarry(AT)wit.ie), Dec 12 2003