A036655 Numbers d_n used in recurrence for series-parallel numbers.

1, 2, 2, 6, 2, 18, 2, 46, 14, 126, 2, 454, 2, 1266, 134, 4222, 2, 14202, 2, 46406, 1274, 155502, 2, 531790, 122, 1792810, 13802, 6126334, 2, 21032794, 2, 72121854, 155510, 248396798, 1382, 857944150, 2, 2964896882, 1792818, 10269600622

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

References

• J. Riordan, An Introduction to Combinatorial Analysis, foot of p. 141.

Formula

G.f.: S'*(1-S)/(1+S), where S = g.f. for A000084.