A253211 a(n) = 8^n + 7.

8, 15, 71, 519, 4103, 32775, 262151, 2097159, 16777223, 134217735, 1073741831, 8589934599, 68719476743, 549755813895, 4398046511111, 35184372088839, 281474976710663, 2251799813685255, 18014398509481991, 144115188075855879, 1152921504606846983

Offset: 0

Author

Vincenzo Librandi, Dec 30 2014

Keywords

• nonn
• easy

Comments

Subsequence of A226825.

Links

• Index entries for linear recurrences with constant coefficients, signature (9,-8).

Crossrefs

Cf. similar sequences listed in A253208.

Cf. A164786, A226825.

Programs

Magma

[8^n+7: n in [0..30]];

Mathematica

Table[8^n + 7, {n, 0, 40}]
8^Range[0,20]+7 (* or *) LinearRecurrence[{9,-8},{8,15},30] (* Harvey P. Dale, Feb 25 2024 *)

Formula

G.f.: (8 - 57*x)/((1 - x)*(1 - 8*x)).

a(n) = 9*a(n-1) - 8*a(n-2) for n>1.