a(n) = (15*2^(2*n+2) + 15*2^(n+2) + 5*2^(n+3)*3^(n+1) - 24*5^(n+1))/120.
A281581
a(n) = (15*2^(2*n+2) + 15*2^(n+2) + 5*2^(n+3)*3^(n+1) - 24*5^(n+1))/120.
Terms
- a(0) =1a(1) =4a(2) =21a(3) =127a(4) =807a(5) =5179a(6) =33111a(7) =210067a(8) =1321887a(9) =8255899a(10) =51225351a(11) =316067107a(12) =1941032367a(13) =11873549419a(14) =72394874391a(15) =440204293747
External references
- oeis: A281581