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 A217941 a(n) = Sum_{k=1..n} k*C(n,k), where C(n,k) = number of binary sequences of length n and curling number k (A216955). 2

%I

%S 2,6,14,32,66,140,282,574,1156,2326,4654,9348,18698,37436,74904,

%T 149896,299794,599780,1199562,2399448,4798996,9598556,19197114,

%U 38395584,76791200,153584626,307169622,614343808,1228687618,2457384892,4914769786,9829557516,19659116482,39318268388

%N a(n) = Sum_{k=1..n} k*C(n,k), where C(n,k) = number of binary sequences of length n and curling number k (A216955).

%C a(n)/2^n appears to be converging to 2.2886...

%H N. J. A. Sloane, <a href="/A217941/b217941.txt">Table of n, a(n) for n = 1..48</a>

%F For n>=1, a(2n+1) = 2*a(2n)+2, while a(2n) is a mystery.

%Y Cf. A216955, A217942.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Oct 23 2012

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Last modified December 6 06:48 EST 2022. Contains 358595 sequences. (Running on oeis4.)