A360198 Number of induced cycles in the 5 X n grid graph.

0, 4, 14, 58, 229, 749, 2180, 6188, 17912, 52620, 154383, 450195, 1309452, 3811888, 11110432, 32392550, 94412963, 275116777, 801676752, 2336222946, 6808405238, 19841419978, 57821971765, 168504312515, 491055599116, 1431039769316, 4170353383134, 12153282490316, 35417189532323

Offset: 1

Author

Andrew Howroyd, Jan 29 2023

Keywords

• nonn
• easy

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..200
• Index entries for linear recurrences with constant coefficients, signature (6,-14,17,-3,-17,16,-2,9,-27,5,19,-3,-2,-5,2).

Crossrefs

Row 5 of A360196.

Formula

G.f.: x^2*(4 - 10*x + 30*x^2 + 9*x^3 - 39*x^4 + 16*x^5 + 49*x^6 + 28*x^7 - 76*x^8 - 58*x^9 + 7*x^10 + 13*x^11 + 9*x^12 - 4*x^13)/((1 - x)^2*(1 - 4*x + 5*x^2 - 3*x^3 - 8*x^4 + 4*x^5 - 2*x^7 - 13*x^8 + 3*x^9 + 14*x^10 + 6*x^11 + x^12 - 2*x^13)).

Extensions

Missing a(1)=0 inserted by Andrew Howroyd, Feb 23 2023