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A104896 a(0) = 0; a(n) = 7*a(n-1) + 7. 3
0, 7, 56, 399, 2800, 19607, 137256, 960799, 6725600, 47079207, 329554456, 2306881199, 16148168400, 113037178807, 791260251656, 5538821761599, 38771752331200, 271402266318407, 1899815864228856, 13298711049601999, 93090977347214000, 651636841430498007 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Conjecture: this is also the number of integers from 0 to 10^n - 1 that lack 0, 1 and 2 as a digit.

Number of monic irreducible polynomials of degree 1 in GF(7)[x1,...,xn]. - Max Alekseyev, Jan 23 2006

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..500

Index entries for linear recurrences with constant coefficients, signature (8,-7).

FORMULA

a(n) = (7^(n+1) - 7) / 6. - Max Alekseyev, Jan 23 2006

a(n) = 7^n+a(n-1) (with a(0)=0). - Vincenzo Librandi, Nov 13 2010

a(n) = 8*a(n-1)-7*a(n-2). G.f.: 7*x / ((x-1)*(7*x-1)). - Colin Barker, Jul 25 2014

MAPLE

a:=n->sum (7^j, j=1..n): seq(a(n), n=0..15); # Zerinvary Lajos, Oct 03 2007

MATHEMATICA

RecurrenceTable[{a[n]==7*a[n-1]+7, a[0]==0}, a, {n, 0, 20}] (* Vaclav Kotesovec, Jul 25 2014 *)

PROG

(PARI) concat(0, Vec(7*x/((x-1)*(7*x-1)) + O(x^100))) \\ Colin Barker, Jul 25 2014

CROSSREFS

Cf. A052386, A052379, A000918, A029858, A080674.

Row n=7 of A228275.

Sequence in context: A264693 A054614 A270240 * A246939 A122996 A092318

Adjacent sequences:  A104893 A104894 A104895 * A104897 A104898 A104899

KEYWORD

easy,nonn

AUTHOR

Alexandre Wajnberg, Apr 24 2005

STATUS

approved

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Last modified October 20 20:08 EDT 2019. Contains 328271 sequences. (Running on oeis4.)