Let a(n) = 2^n + a(n-2) for n > 1, a(0) = 3, and a(1) = 3.
3, 3, 7, 11, 23, 43, 87, 171, 343, 683, 1367, 2731, 5463, 10923, 21847, 43691, 87383, 174763, 349527, 699051, 1398103, 2796203, 5592407, 11184811, 22369623, 44739243, 89478487, 178956971, 357913943, 715827883, 1431655767, 2863311531, 5726623063
0
Conjectured locations where 2 occurs in the sequence S000382.
T. D. Noe, Plot of 101 terms
T. D. Noe, Table of 101 terms
Thomas Koshy, Triangular Arrays with Applications, Oxford, 2011, p. 171.
(Mma) t = {3, 3}; Do[AppendTo[t, 2^n + t[[-2]]], {n, 2, 30}]; t
Cf. S000382.
nonn
T. D. Noe, Nov 24 2014