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A135882 Column 1 of triangle A135880. 6

%I #5 Mar 30 2012 18:37:07

%S 1,2,7,34,215,1698,16220,182714,2378780,35219202,585245185,

%T 10797322816,219163958124,4856832298391,116735215192864,

%U 3025759884533190,84155831914971391,2500599947944218716,79072271422935678302

%N Column 1 of triangle A135880.

%H Paul D. Hanna, <a href="/A135882/b135882.txt">Table of n, a(n) for n = 0..79</a>

%e Equals column 1 of triangle P=A135880:

%e 1;

%e 1, 1;

%e 2, 2, 1;

%e 6, 7, 3, 1;

%e 25, 34, 15, 4, 1;

%e 138, 215, 99, 26, 5, 1;

%e 970, 1698, 814, 216, 40, 6, 1; ...

%e where column k of P^2 equals column 0 of P^(2k+2)

%e such that column 0 of P^2 equals column 0 of P shift left.

%o (PARI) {a(n)=local(P=Mat(1),R,PShR);if(n==0,1,for(i=0,n, PShR=matrix(#P,#P, r,c, if(r>=c,if(r==c,1,if(c==1,0,P[r-1,c-1]))));R=P*PShR; R=matrix(#P+1, #P+1, r,c, if(r>=c, if(r<#P+1,R[r,c], if(c==1,(P^2)[ #P,1],(P^(2*c-1))[r-c+1,1])))); P=matrix(#R, #R, r,c, if(r>=c, if(r<#R,P[r,c], (R^c)[r-c+1,1]))));P[n+2,2])}

%Y Cf. A135880; other columns: A135881, A135883, A135884.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Dec 15 2007

%E Error in entries (false comma) corrected by _N. J. A. Sloane_, Jan 23 2008

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Last modified March 28 16:58 EDT 2024. Contains 371254 sequences. (Running on oeis4.)