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A003464 (6^n - 1)/5.
(Formerly M4425)
23
0, 1, 7, 43, 259, 1555, 9331, 55987, 335923, 2015539, 12093235, 72559411, 435356467, 2612138803, 15672832819, 94036996915, 564221981491, 3385331888947, 20311991333683, 121871948002099, 731231688012595, 4387390128075571 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

a(n) = A125118(n,5) for n>4. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 21 2006

Let A be the Hessenberg matrix of order n, defined by: A[1,j]=1, A[i,i]:=6, (i>1), A[i,i-1]=-1, and A[i,j]=0 otherwise. Then, for n>=1, a(n)=det(A). [From Milan R. Janjic (agnus(AT)blic.net), Feb 21 2010]

Let A be the Hessenberg matrix of order n, defined by: A[1,j]=1, A[i,i]:=7, (i>1), A[i,i-1]=-1, and A[i,j]=0 otherwise. Then, for n>1, a(n-1)=(-1)^n*charpoly(A,1). [From Milan R. Janjic (agnus(AT)blic.net), Feb 21 2010]

Repunits to base 6. A repunit consisting of zero 1s (empty string) gives the empty sum, i.e. 0 (only case where leading zero is shown, for convenience) - Daniel Forgues, Jul 08 2011

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

C. Banderier and D. Merlini, Lattice paths with an infinite set of jumps, FPSAC02, Melbourne, 2002.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 375

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

FORMULA

Binomial transform of A003948. If preceded by 0, then binomial transform of powers of 5, A000351 (preceded by 0). - Paul Barry (pbarry(AT)wit.ie), Mar 28 2003

a(n) = Sum{k=1..n, C(n, k)5^(k-1) }. E.g.f.: (exp(6x) - exp(x))/5 (offset 0). - Paul Barry (pbarry(AT)wit.ie), Mar 28 2003

G.f.: 1/((1-1x)(1-6x)) - Lambert Klasen (lambert.klasen(AT)gmx.net), Feb 06 2005

a(n) = 6*a(n-1)+1 with a(1)=1. [From Vincenzo Librandi, Nov 17 2010]

MAPLE

a:=n->sum(6^(n-j), j=1..n): seq(a(n), n=1..21); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 04 2007

A003464:=1/(6*z-1)/(z-1); [Conjectured by S. Plouffe in his 1992 dissertation.]

a[0]:=0:a[1]:=1:for n from 2 to 50 do a[n]:=5*a[n-1]+6*a[n-2]+2 od: seq(a[n], n=1..33); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 14 2008]

MATHEMATICA

lst={}; Do[p=(6^n-1)/5; AppendTo[lst, p], {n, 0, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Sep 29 2008]

Alternate: (6^Range[20]-1)/5 [from Harvey P. Dale, Dec. 14, 2010]

PROG

(PARI) for(n=0, 10, print1(polcoeff(1/((1-1*x)*(1-6*x)), n), ", ")) for(n=1, 10, print1((6^n-1)/5, ", "))

(Other) sage: [lucas_number1(n, 7, 6) for n in xrange(1, 22)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 23 2009]

(Other) sage: [gaussian_binomial(n, 1, 6) for n in xrange(1, 22)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 28 2009]

CROSSREFS

Sequence in context: A043553 A049609 A161728 * A022036 A015451 A194779

Adjacent sequences:  A003461 A003462 A003463 * A003465 A003466 A003467

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 21 2006

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Last modified February 14 22:52 EST 2012. Contains 205685 sequences.