A297663 a(n) = 5*n + 2^n.

1, 7, 14, 23, 36, 57, 94, 163, 296, 557, 1074, 2103, 4156, 8257, 16454, 32843, 65616, 131157, 262234, 524383, 1048676, 2097257, 4194414, 8388723, 16777336, 33554557, 67108994, 134217863, 268435596, 536871057, 1073741974, 2147483803, 4294967456, 8589934757

Offset

0,2

Comments

Also the number of chordless cycles in 2n-crossed prism graph for n >= 3.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Eric Weisstein's World of Mathematics, Chordless Cycle

Eric Weisstein's World of Mathematics, Crossed Prism Graph

Index entries for linear recurrences with constant coefficients, signature (4,-5,2)

Formula

a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3).

G.f.: (-1 - 3*x + 9*x^2)/((-1 + x)^2*(-1 + 2*x)).

Mathematica

Table[5 n + 2^n, {n, 0, 20}]
LinearRecurrence[{4, -5, 2}, {7, 14, 23}, {0, 20}]
seq = CoefficientList[Series[(-1 - 3 x + 9 x^2)/((-1 + x)^2 (-1 + 2 x)), {x, 0, 20}], x]

Prog

(Magma) I:=[1, 7, 14]; [n le 3 select I[n] else 4*Self(n-1)- 5*Self(n-2)+2*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Feb 21 2018

Crossrefs

Sequence in context: A050953 A333859 A232825 * A190779 A188383 A025011

Adjacent sequences: A297660 A297661 A297662 * A297664 A297665 A297666

Keyword

nonn,easy

Author

Eric W. Weisstein, Jan 02 2018

Status

approved