A036654 Triangle of series-parallel numbers.

1, 1, 1, 2, 2, 2, 4, 6, 8, 8, 10, 18, 34, 52, 52, 24, 58, 136, 288, 472, 472, 66, 186, 538, 1424, 3224, 5504, 5504, 180, 614, 2080, 6648, 18888, 44712, 78416, 78416, 522, 2034, 7970, 29700, 101340, 302096, 738448, 1320064, 1320064

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy
• tabl
• nice

Examples

			Triangle begins
  1;
  1, 1;
  2, 2, 2;
  4, 6, 8, 8;
  ...
		

References

• J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 142.

Extensions

a(35) corrected by Sean A. Irvine, Nov 15 2020