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

1,4

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).

Links

Table of n, a(n) for n=1..33.

Crossrefs

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

Sequence in context: A024500 A318870 A000087 * A095067 A225564 A032259

Adjacent sequences: A145664 A145665 A145666 * A145668 A145669 A145670

Keyword

nonn,base,more

Author

W. Edwin Clark, Mar 17 2009

Extensions

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

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

Status

approved