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A101907 a(0) = 1, a(1) = 1, a(2) = 2, for n>2 a(n) = 5*a(n-1) - 5*a(n-2) + a(n-3). +0
1
1, 2, 6, 21, 77, 286, 1066, 3977, 14841, 55386, 206702, 771421, 2878981, 10744502, 40099026, 149651601, 558507377, 2084377906, 7779004246, 29031639077, 108347552061, 404358569166, 1509086724602, 5631988329241, 21018866592361 (list; graph; listen)
OFFSET

0,2

COMMENT

Consider the matrix M=[1,1,0; 1,3,1; 0,1,1]; Use (M^n)[1,1] and the characteristic polynomial of M = x^3 - 5*x^2 + 5*x - 1 to define the recursion.

a(n+1)/a(n) converges to 2 + sqrt(3) as n goes to infinity, the largest root of the characteristic polynomial. a(n) = A061278(n) + 1; a(n+1)-a(n) = A001353(n) = (M^n)[1,2]; (M^n)[1,3] = A061278(n-1) for n>0; (M^n)[1,1]+(M^n)[1,3] = A001835(n); (M^n)[1,1]+(M^n)[1,2]+(M^n)[1,3] = A001075(n)

PROGRAM

(PARI) M=[ 1, 1, 0; 1, 3, 1; 0, 1, 1]; for(i=0, 20, print1((M^i)[1, 1], ", "))

CROSSREFS

Cf. A061278, A001353, A001835, A001075, A002194.

Adjacent sequences: A101904 A101905 A101906 this_sequence A101908 A101909 A101910

Sequence in context: A131792 A101265 A101879 this_sequence A063023 A124292 A129776

KEYWORD

nonn

AUTHOR

Lambert Klasen (lambert.klasen(AT)gmx.net) and Gary W. Adamson (qntmpkt(AT)yahoo.com), Jan 28 2005

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Last modified May 15 13:16 EDT 2008. Contains 139641 sequences.


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