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A036654 Triangle of series-parallel numbers. 1

%I

%S 1,1,1,2,2,2,4,6,8,8,10,18,34,52,52,24,58,136,288,472,472,66,186,538,

%T 1424,3224,5504,5504,180,614,2080,6648,18888,44712,78416,78416,522,

%U 2034,7970,29700,101340,302096,738448,1320064,1320064

%N Triangle of series-parallel numbers.

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

%e Triangle begins

%e 1;

%e 1, 1;

%e 2, 2, 2;

%e 4, 6, 8, 8;

%e ...

%K nonn,easy,tabl,nice

%O 0,4

%A _N. J. A. Sloane_

%E a(35) corrected by _Sean A. Irvine_, Nov 15 2020

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Last modified October 2 00:05 EDT 2022. Contains 357173 sequences. (Running on oeis4.)