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A156202 a(n) = 2*a(n-1)+3 for n > 1, a(1) = 10. 2
10, 23, 49, 101, 205, 413, 829, 1661, 3325, 6653, 13309, 26621, 53245, 106493, 212989, 425981, 851965, 1703933, 3407869, 6815741, 13631485, 27262973, 54525949, 109051901, 218103805, 436207613, 872415229, 1744830461, 3489660925, 6979321853, 13958643709 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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

FORMULA

a(n) = -3+13*2^(n-1).

G.f.: x*(10-7*x)/(1-3*x+2*x^2). - Vincenzo Librandi, May 02 2012

a(n) = 3*a(n-1) - 2*a(n-2). - Vincenzo Librandi, May 02 2012

MATHEMATICA

LinearRecurrence[{3, -2}, {10, 23}, 30] (* Vincenzo Librandi, May 02 2012 *)

NestList[2#+3&, 10, 40] (* Harvey P. Dale, Jul 08 2019 *)

PROG

(Magma) I:=[10, 23]; [n le 2 select I[n] else 3*Self(n-1)-2*Self(n-2): n in [1..30]]; // Vincenzo Librandi, May 02 2012

(Python)

from itertools import accumulate

def f(an, _): return 2*an + 3

print(list(accumulate([10]*31, f))) # Michael S. Branicky, Oct 23 2021

CROSSREFS

Sequence in context: A140674 A072245 A135277 * A266080 A316093 A262485

Adjacent sequences:  A156199 A156200 A156201 * A156203 A156204 A156205

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Feb 08 2009

EXTENSIONS

Definition and closed form corrected by Paolo P. Lava, Feb 13 2009

STATUS

approved

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Last modified September 28 01:24 EDT 2022. Contains 357063 sequences. (Running on oeis4.)