A051039 4-Stohr sequence.

1, 2, 4, 8, 16, 31, 46, 61, 76, 91, 106, 121, 136, 151, 166, 181, 196, 211, 226, 241, 256, 271, 286, 301, 316, 331, 346, 361, 376, 391, 406, 421, 436, 451, 466, 481, 496, 511, 526, 541, 556, 571, 586, 601, 616, 631, 646, 661, 676, 691, 706, 721, 736, 751

Offset: 1

Author

Eric W. Weisstein

Keywords

• nonn
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Eric Weisstein's World of Mathematics, Stoehr Sequence.
• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Cf. A033627, A026474, A051040.

Programs

Mathematica

Join[{1,2,4,8},Range[16,3001,15]] (* Vladimir Joseph Stephan Orlovsky, Jan 27 2012 *)
LinearRecurrence[{2,-1},{1,2,4,8,16,31},60] (* Harvey P. Dale, Dec 25 2016 *)

PARI

a(n)=if(n>4,15*n-59,2^(n-1)) \\ Charles R Greathouse IV, Jun 20 2024

Formula

a(n) = 15*n-59 for n>4. a(n) = 2*a(n-1)-a(n-2) for n>6. G.f.: x*(7*x^5+4*x^4+2*x^3+x^2+1)/(x-1)^2. - Colin Barker, Sep 19 2012