A048223 a(n)=T(n,1)+T(n,n), array T given by A048212.

4, 4, 11, 19, 29, 39, 54, 72, 89, 113, 137, 163, 189, 216, 254, 288, 323, 363, 402, 446, 495, 544, 593, 651, 710, 772, 835, 898, 964, 1036, 1106, 1185, 1263, 1341, 1420, 1504, 1591, 1681, 1770, 1860, 1963, 2063, 2165, 2271, 2378

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Crossrefs

Cf. A004979.

Formula

a(n) = 2*A004979(n+1) - A004979(n) - 1. - Sean A. Irvine, Jun 05 2021