A023190 Conjecturally, maximum number of primes in an infinitely-recurring prime pattern of width 2*n-1.

1, 2, 2, 3, 4, 4, 5, 5, 6, 6, 7, 6, 7, 8, 8, 9, 10, 10, 11, 10, 11, 12, 12, 12, 13, 14, 13, 14, 15, 15, 16, 16, 16, 17, 17, 18, 18, 18, 19, 19, 20, 20, 21, 21, 21, 22, 22, 23, 23, 23, 24, 24, 24, 24, 24, 25, 25, 26, 26, 26, 27, 27, 27, 28, 28, 29, 29, 29, 30, 30

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Of all the patterns in A023192 (i.e. infinitely-recurring prime patterns) for length 2*n-1, consider those starting and ending with "p". This sequence gives the maximal count of "p"'s in any of those patterns. The companion sequence A023191, gives the number of patterns achieving that maximum. - Sean A. Irvine, May 27 2019

Examples

			a(3) concerns patterns of length 5. Of the 10 potential patterns (ccccc, ccccp, cccpc, ccpcc, cpccc, pcccc, ccpcp, cpcpc, pcpcc, pcccp), only pcccp starts and ends with a "p", and it contains 2 "p"'s, so a(3) = 2, and A023191(3) = 1. - _Sean A. Irvine_, May 27 2019
		

Links

• Martin Raab, Table of n, a(n) for n = 1..1166
• Thomas J Engelsma, Permissible Patterns

Crossrefs

Cf. A023191, A023192.

Extensions

More terms from Thomas J Engelsma web page added by Martin Raab, Oct 31 2021