A220088 a(n) = 2^n - 81.

-80, -79, -77, -73, -65, -49, -17, 47, 175, 431, 943, 1967, 4015, 8111, 16303, 32687, 65455, 130991, 262063, 524207, 1048495, 2097071, 4194223, 8388527, 16777135, 33554351, 67108783, 134217647, 268435375, 536870831, 1073741743, 2147483567, 4294967215

Offset

0,1

Links

Table of n, a(n) for n=0..32.

Index entries for linear recurrences with constant coefficients, signature (3,-2).

Formula

From Chai Wah Wu, Jan 17 2020: (Start)

a(n) = 3*a(n-1) - 2*a(n-2) for n > 1.

G.f.: (161*x - 80)/((x - 1)*(2*x - 1)). (End)

From Elmo R. Oliveira, Nov 11 2023: (Start)

a(n) = 2*a(n-1) + 81 with a(0) = -80.

E.g.f.: exp(2*x) - 81*exp(x). (End)

Mathematica

Table[2^n - 81, {n, 0, 40}] (* T. D. Noe, Dec 04 2012 *)

Crossrefs

Cf. A000225, A036563, A185346, A220087.

Sequence in context: A306414 A207144 A200720 * A126783 A255477 A296878

Adjacent sequences: A220085 A220086 A220087 * A220089 A220090 A220091

Keyword

sign,easy

Author

Andreas Rieber, Dec 04 2012

Status

approved