a(n) = Sum_{k=0..floor(n/2)} T(n,k) * T(n,k+1), with T given by A026009.
A027288
a(n) = Sum_{k=0..floor(n/2)} T(n,k) * T(n,k+1), with T given by A026009.
Terms
- a(0) =1a(1) =4a(2) =12a(3) =46a(4) =145a(5) =552a(6) =1820a(7) =6918a(8) =23562a(9) =89645a(10) =312664a(11) =1191885a(12) =4232345a(13) =16170728a(14) =58229100a(15) =222997812a(16) =811985790a(17) =3116622123a(18) =11451785640a(19) =44047806725a(20) =163072988442a(21) =628465576101
External references
- oeis: A027288