

A296600


Number of pairs of binary strings (u,v) with u of length n, v of length 2n, and u and v mutually overlapping.


1



2, 26, 244, 2070, 17100, 138684, 1117200, 8966634, 71848980, 575237140, 4603664560, 36836229636, 294717238960
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OFFSET

1,1


COMMENTS

We say the pair (u,v) is mutually overlapping if some nonempty prefix of u is a suffix of v, and vice versa. For n = 3, an example is (011,110110). If C(m,n) is the number of mutually overlapping ordered pairs (u,v) with u=m and v=n, then C(m,2m+a) = 2^a C(m,2m) for a >= 0, so the case enumerated by this sequence is in some sense the most useful to understand.


LINKS

Table of n, a(n) for n=1..13.


CROSSREFS

Cf. A295863.
Sequence in context: A280556 A198960 A289263 * A187252 A096233 A126673
Adjacent sequences: A296597 A296598 A296599 * A296601 A296602 A296603


KEYWORD

nonn,more


AUTHOR

Jeffrey Shallit, Feb 15 2018


EXTENSIONS

a(9)a(13) from Lars Blomberg, Nov 30 2018


STATUS

approved



