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

0, 1, 1, 2, 1, 2, 4, 11, 13, 19, 29, 43, 107, 169, 350, 603, 1134, 2070, 3803, 7502, 13989, 26495, 50826, 97369, 185827, 357307, 690577, 1332382, 2565110, 4958962, 9594425, 18569626, 36009794

Offset: 1

Author

W. Edwin Clark, Mar 17 2009

Keywords

• nonn
• base
• more

Comments

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).

Crossrefs

Cf. A104080, A014234, A145668, A145669, A145670, A145671, A145672, A145673, A145674, A158576, A158577, A158578, A158579.

Extensions

a(18)-a(31) from Max Alekseyev, May 12 2011

a(32)-a(33) from Max Alekseyev, Dec 23 2024