29080507

Appears in sequences

• a(n) = a(n-1)+a(n-2)+a(n-3)+2*a(n-4), a(0)=1, a(1)=3, a(2)=7, a(3)=15.at n=24A139806
• a(n) = (10*4^n - 3*(-4)^n - 22)/30.at n=12A176963