A228789 a(n) = 2^L(n) + 1, where L(n) is A000032(n).

5, 3, 9, 17, 129, 2049, 262145, 536870913, 140737488355329, 75557863725914323419137, 10633823966279326983230456482242756609, 803469022129495137770981046170581301261101496891396417650689

Offset: 0

Author

M. Tamba and Yeshwant Shivrai Valaulikar, Sep 04 2013

Keywords

• nonn
• easy

Crossrefs

Cf. A000032.

Programs

Mathematica

Table[1 + 2^LucasL[n], {n, 0, 11}] (* T. D. Noe, Sep 17 2013 *)

Formula

a(n+2) = a(n)*a(n+1) - a(n) - a(n+1) + 2.

Binet type formula: log_2(a(n)-1) = r^n - s^n where r and s are the roots of x^2-x-1 = 0. (This is true the definition).