A036654 - OEIS

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

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

0,4

REFERENCES

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

LINKS

Table of n, a(n) for n=0..44.

EXAMPLE

Triangle begins

1, 1;

2, 2, 2;

4, 6, 8, 8;

...

CROSSREFS

Sequence in context: A341095 A090858 A187504 * A262669 A345256 A291299

Adjacent sequences: A036651 A036652 A036653 * A036655 A036656 A036657

KEYWORD

nonn,easy,tabl,nice

AUTHOR

N. J. A. Sloane

EXTENSIONS

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

STATUS

approved