1,1

B. Malesevic: Some combinatorial aspects of differential operation composition on the space R^n, Univ. Beograd, Publ. Elektrotehn. Fak., Ser. Mat. 9 (1998), 29-33.

B. Malesevic, Some combinatorial aspects of differential operation composition on the space R^n

a(k+6)=5*a(k+4)-6*a(k+2)+a(k)

NUM := proc(k :: integer) local i, j, n, Fun, Identity, v, A; n := 10; # <- DIMENSION Fun := (i, j)->piecewise(((j=i+1) or (i+j=n+1)), 1, 0); Identity := (i, j)->piecewise(i=j, 1, 0); v := matrix(1, n, 1); A := piecewise(k>1, (matrix(n, n, Fun))^(k-1), k=1, matrix(n, n, Identity)); return(evalm(v&*A&*transpose(v))[1, 1]); end:

Cf. A090989-A090994.

Equals 2 * A090990.

Sequence in context: A125689 A100992 A014006 this_sequence A064485 A007938 A007937

Adjacent sequences: A090992 A090993 A090994 this_sequence A090996 A090997 A090998

nonn

Branko Malesevic (malesevic(AT)kiklop.etf.bg.ac.yu), Feb 29 2004