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A155640 7^n-5^n+1^n 20
1, 3, 25, 219, 1777, 13683, 102025, 745419, 5374177, 38400483, 272709625, 1928498619, 13597146577, 95668307283, 672119557225, 4717043931819, 33080342678977, 231867574534083, 1624598900644825, 11379821699045019 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..19.

Index entries for linear recurrences with constant coefficients, signature (13,-47,35).

FORMULA

G.f.: 1/(1-7*x)-1/(1-5*x)+1/(1-x). E.g.f.: e^(7*x)-e^(5*x)+e^x.

a(n)=12*a(n-1)-35*a(n-2)+24 with a(0)=1, a(1)=3 - Vincenzo Librandi, Jul 21 2010

PROG

(PARI) a(n)=7^n-5^n+1 \\ Charles R Greathouse IV, Sep 24 2015

CROSSREFS

Cf. A155624, A155625, A155626, A155627, A155628, A155629, A155630, A155631, A155632, A155633, A155634, A155635, A155636, A155637, A155638, A155639.

Sequence in context: A222052 A230718 A112240 * A024217 A199679 A118726

Adjacent sequences:  A155637 A155638 A155639 * A155641 A155642 A155643

KEYWORD

nonn,easy

AUTHOR

Mohammad K. Azarian, Jan 30 2009

STATUS

approved

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Last modified February 27 05:37 EST 2021. Contains 341649 sequences. (Running on oeis4.)