1,1

Also number of meaningful compositions of the n-th order of the differential operations and Gateaux directional derivative on the space R^6. - Branko Malesevic and Ivana Jovovic (ivana121(AT)EUnet.yu), Jun 21 2007

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

B. Malesevic and I. Jovovic, TheCompositions of the Differential Operations and Gateaux DirectionalDerivative .

a(k+5)=a(k+3)+3*a(k+2)-2*a(k+1)-a(k)

NUM := proc(k :: integer) local i, j, n, Fun, Identity, v, A; n := 7; # <- 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-A090995.

Partial sums of pairwise sums of A065455.

Cf. A000079, A007283, A020701, A020714, A129638.

Sequence in context: A129727 A075642 A032690 this_sequence A034780 A137165 A137177

Adjacent sequences: A090989 A090990 A090991 this_sequence A090993 A090994 A090995

nonn

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

More terms from Branko Malesevic and Ivana Jovovic (ivana121(AT)EUnet.yu), Jun 21 2007