A027208 a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026725.

1, 4, 19, 72, 338, 1289, 6027, 23117, 107746, 415058, 1929383, 7456777, 34584731, 134005510, 620344059, 2408498148, 11131638368, 43289074671, 199800878749, 778025282080, 3586777011141, 13982303458588, 64394916131100, 251261623174835, 1156165698462868, 4514741175877259

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Programs

Maple

A027208 := proc(n)
    add( A026725(n,k)*A026725(n,k+1),k=0..n-1) ;
end proc: # R. J. Mathar, Oct 21 2019

Extensions

Name corrected by R. J. Mathar, Oct 21 2019

More terms from Sean A. Irvine, Oct 24 2019