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A145667 a(n) = number of components of the graph P(n,2) (defined in Comments). 12

%I

%S 0,1,1,2,1,2,4,11,13,19,29,43,107,169,350,603,1134,2070,3803,7502,

%T 13989,26495,50826,97369,185827,357307,690577,1332382,2565110,4958962,

%U 9594425

%N a(n) = number of components of the graph P(n,2) (defined in Comments).

%C Let H(n,b) be the Hamming graph whose vertices are the sequences of length n over the alphabet {0,1,...,b-1} with adjacency being defined by having Hamming distance 1. Let P(n,b) be the subgraph of H(n,b) induced by the set of vertices which are base b representations of primes with n digits (not allowing leading 0 digits).

%Y Cf. A145667-A145674, A104080, A014234.

%K nonn,base,more

%O 1,4

%A _W. Edwin Clark_, Mar 17 2009

%E a(18)-a(31) from _Max Alekseyev_, May 12 2011

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Last modified May 16 21:28 EDT 2021. Contains 343951 sequences. (Running on oeis4.)