A105837 Numbers n such that n^2 = 11*m^2 + 11*m + 1.

1, 131, 529, 52139, 210541, 20751191, 83794789, 8258921879, 33350115481, 3287030156651, 13273262166649, 1308229743425219, 5282724992210821, 520672150853080511, 2102511273637740109, 207226207809782618159, 836794204182828352561

Offset: 1

Author

Pierre CAMI, Apr 22 2005

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (0,398,0,-1).

Crossrefs

Cf. A105838 (associated m).

Programs

Mathematica

LinearRecurrence[{0, 398, 0, -1}, {1, 131, 529, 52139}, 17]

Formula

a(1)=1, a(2)=131, a(3)=398*a(1)+a(2), a(4)=398*a(2)+a(1), a(n)=398*a(n-2)-a(n-4) for n>4.

G.f.: x*(1+x)*(1+130*x+x^2)/((1-20*x+x^2)*(1+20*x+x^2)). [Bruno Berselli, Feb 21 2013]

Extensions

More terms from Bruno Berselli, Feb 21 2013