login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A skew Jacobsthal-Pascal matrix.
1

%I #11 Jan 26 2020 20:11:30

%S 1,0,1,0,1,3,0,0,2,5,0,0,1,7,11,0,0,0,3,16,21,0,0,0,1,12,41,43,0,0,0,

%T 0,4,34,94,85,0,0,0,0,1,18,99,219,171,0,0,0,0,0,5,60,261,492,341,0,0,

%U 0,0,0,1,25,195,678,1101,683,0,0,0,0,0,0,6,95,576,1692,2426,1365,0,0,0,0,0

%N A skew Jacobsthal-Pascal matrix.

%C T(n,n) is A001045(n), row sums are A006130, column sums are A002605. Compare with [0,1,-1,0,0,..] DELTA [1,2,-2,0,0,...] where DELTA is the operator defined in A084938. A skewed version of the Riordan array (1/(1-x-2x^2),x/(1-x-2x^2)) (A073370).

%C Modulo 2, this sequence gives A106344. - _Philippe Deléham_, Dec 18 2008

%F From _Philippe Deléham_: (Start)

%F G.f.: 1/(1-yx(1-x)-2x^2*y*2);

%F Number triangle T(n, k) = Sum_{j=0..2k-n} C(n-k+j, n-k)*C(j, 2k-n-j)*2^(2k-n-j);

%F T(n, k) = A073370(k, n-k); T(n, k) = T(n-1, k-1) + T(n-2, k-1) + 2*T(n-2, k-2). (End)

%e Rows begin

%e 1;

%e 0, 1;

%e 0, 1, 3;

%e 0, 0, 2, 5;

%e 0, 0, 1, 7, 11;

%e 0, 0, 0, 3, 16, 21;

%e 0, 0, 0, 1, 12, 41, 43;

%e 0, 0, 0, 0, 4, 34, 94, 85;

%e 0, 0, 0, 0, 1, 18, 99, 219, 171;

%e 0, 0, 0, 0, 0, 5, 60, 261, 492, 341;

%e 0, 0, 0, 0, 0, 1, 25, 195, 678, 1101, 683;

%Y Cf. A111006.

%K easy,nonn,tabl

%O 0,6

%A _Paul Barry_, Oct 05 2005