A146511 Numbers congruent to {5, 17} modulo 66.

5, 17, 71, 83, 137, 149, 203, 215, 269, 281, 335, 347, 401, 413, 467, 479, 533, 545, 599, 611, 665, 677, 731, 743, 797, 809, 863, 875, 929, 941, 995, 1007, 1061, 1073, 1127, 1139, 1193, 1205, 1259, 1271, 1325, 1337, 1391, 1403, 1457, 1469, 1523, 1535, 1589

Offset: 1

Author

Artur Jasinski, Oct 30 2008

Keywords

• nonn
• easy

Comments

Positive integers k such that Hypergeometric[k/22,(22-k)/22,1/2,3/4] = 2*cos(Pi/11).

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (1,1,-1).

Crossrefs

Cf. A146507, A146509, A146510, A146512.

Programs

Mathematica

Select[Range[1600],MemberQ[{5,17},Mod[#,66]]&]  (* Ray Chandler, Dec 06 2016 *)
#+{5,17}&/@(66*Range[0,30])//Flatten (* Harvey P. Dale, Mar 26 2019 *)

Formula

a(2k-1) = 66*(k-1)+5, a(2k) = 66*(k-1)+17, where k>0.

G.f.: x*(5 + 12*x + 49*x^2)/((1 - x)^2*(1 + x)). - Ilya Gutkovskiy, Dec 06 2016

E.g.f.: 49 + ((66*x - 77)*exp(x) - 21*exp(-x))/2. - David Lovler, Sep 10 2022

Extensions

Description, formula and crossrefs corrected by Ray Chandler, Dec 06 2016