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

1,1

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

Formula

A000040 INTERSECT A187220.

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 *)

Crossrefs

Cf. A000040, A139253, A187220.

Sequence in context: A127781 A271918 A165580 * A122094 A260350 A270384

Adjacent sequences: A187219 A187220 A187221 * A187223 A187224 A187225

Keyword

nonn

Author

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

Extensions

More terms from Nathaniel Johnston, Mar 22 2011

Status

approved