A187222 Gullwing primes: primes in the gullwing sequence A187220.

3, 7, 23, 31, 47, 71, 191, 311, 367, 503, 607, 967, 1303, 1367, 1439, 1471, 1663, 1871, 2399, 4951, 5471, 5623, 6263, 9431, 10103, 10271, 10687, 12119, 12511, 14431, 14879, 15647, 21871, 22111, 22271, 22807, 23039, 24223, 24919

Offset: 1

Author

Omar E. Pol, Mar 09 2011, Mar 10 2011

Keywords

• nonn

Links

• Nathaniel Johnston, Table of n, a(n) for n = 1..3406
• David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.]
• N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

Crossrefs

Cf. A000040, A139253, A187220.

Programs

Mathematica

m = 200 (* number of gullwing terms *); s = (2*(x/((1-x)*(1 + 2*x))))*(1 + 2*x*Product[1 + x^(2^k-1) + 2*x^2^k, {k, 0, Ceiling[Log[2, m]]}]) + O[x]^(m-1); Select[CoefficientList[s, x] + 1, PrimeQ] (* Jean-François Alcover, Jul 23 2017 *)

Formula

A000040 INTERSECT A187220.

Extensions

More terms from Nathaniel Johnston, Mar 22 2011