A158576 a(n) = number of components of the graph P(n,10) (defined in Comments).
1, 1, 1, 1, 1, 7, 38, 365, 3355, 33586
Offset: 1
Examples
The 6-digit primes 294001, 505447, 584141, 604171, 929573, 971767 (cf. A050249) have the property that changing any single digit always gives a composite number, so these are isolated nodes in the graph P(6,10) (which also has one large connected component).
Crossrefs
Extensions
a(8) from W. Edwin Clark, Mar 31 2009
a(9)-a(10) from Max Alekseyev, Dec 23 2024
Comments