A098730 Sum[i=0..n, Sum[j=0..n, C(n-i,i+j) * C(n-j,i+j) ]].

1, 1, 5, 14, 46, 145, 462, 1465, 4641, 14671, 46298, 145858, 458811, 1441204, 4521255, 14167145, 44344445, 138665650, 433218100, 1352333899, 4218220602, 13148256139, 40956562683, 127501720725, 396702130246, 1233632920766

Offset

0,3

Links

Table of n, a(n) for n=0..25.

Mathematica

Table[Sum[Sum[Binomial[n-i, i+j]Binomial[n-j, i+j], {j, 0, n}], {i, 0, n}], {n, 0, 30}] (* Harvey P. Dale, Jan 25 2023 *)

Crossrefs

Sequence in context: A176640 A126729 A336006 * A244236 A163608 A081496

Adjacent sequences: A098727 A098728 A098729 * A098731 A098732 A098733

Keyword

nonn

Author

Ralf Stephan, Oct 28 2004

Status

approved