cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A085143 Triangle table from number wall of reversion of Fibonacci numbers.

This page as a plain text file.
%I A085143 #9 Jul 21 2023 07:48:48
%S A085143 1,-1,-1,-1,-1,-1,1,0,2,1,1,-2,4,3,1,-1,3,-11,-5,-5,-1,-1,-1,-34,10,
%T A085143 -20,-8,-1,1,11,106,-116,96,44,13,1,1,15,368,-328,716,86,125,21,1,-1,
%U A085143 13,-1324,-1344,-5634,1866,-1063,-316,-34,-1,-1,77,-4811,-17235
%N A085143 Triangle table from number wall of reversion of Fibonacci numbers.
%F A085143 T(n, k) = det(f(i+j-1+k-n)_{i, j=1..n}) where f(n)=A007440(n).
%F A085143 T(n, k) = (-1)^[(n+k-1)/2]*T(k-1, n-1) if 1<=k<=n.
%e A085143 T(4,2)=0 since det([0,0,1,-1; 0,1,-1,0; 1,-1,0,2; -1,0,2,-3])=0.
%e A085143     1
%e A085143    -1    -1
%e A085143    -1    -1    -1
%e A085143     1     0     2     1
%e A085143     1    -2     4     3     1
%e A085143    -1     3   -11    -5    -5    -1
%e A085143    -1    -1   -34    10   -20    -8    -1
%e A085143     1    11   106  -116    96    44    13     1
%e A085143     1    15   368  -328   716    86   125    21     1
%e A085143    -1    13 -1324 -1344 -5634  1866 -1063  -316   -34    -1
%p A085143 A085143 := proc(n,k)
%p A085143     local A,r,c ;
%p A085143     A := Matrix(n,n) ;
%p A085143     for r from 1 to n do
%p A085143     for c from 1 to n do
%p A085143         A[r,c] :=  A007440(r+c-1+k-n) ;
%p A085143     end do:
%p A085143     end do:
%p A085143     Determinant(A) ;
%p A085143 end proc:
%p A085143 seq(seq(A085143(n,k),k=1..n),n=1..12) ; # _R. J. Mathar_, Jul 21 2023
%o A085143 (PARI) {f(n)=polcoeff((-1-x+sqrt(1+2*x+5*x^2+x^2*O(x^n)))/(2*x),n)} \\ A007440
%o A085143 {T(n,k)=matdet(matrix(n,n,i,j,f(i+j-1+k-n)))}
%Y A085143 Cf. A007440.
%K A085143 sign,tabl
%O A085143 1,9
%A A085143 _Michael Somos_, Jun 19 2003