A167194 - OEIS

%I #15 Jun 29 2024 16:44:55

%S 1,2,1,1,2,1,0,1,2,1,0,0,1,2,1,0,0,0,1,2,1,0,0,0,0,1,2,1,0,0,0,0,0,1,

%T 2,1,0,0,0,0,0,0,1,2,1,0,0,0,0,0,0,0,1,2,1,0,0,0,0,0,0,0,0,1,2,1,0,0,

%U 0,0,0,0,0,0,0,1,2,1,0,0,0,0,0,0,0,0,0,0,1,2,1

%N Triangle read by rows. A130713 in the columns.

%F From _Peter Bala_, Sep 12 2012: (Start)

%F T(n,k) = binomial(2,n-k).

%F O.g.f.: (1+x)^2/(1-t*x).

%F Riordan array ((1+x)^2,x).

%F Matrix inverse is signed version of A004736. (End)

%e Table begins:

%e   1;

%e   2,1;

%e   1,2,1;

%e   0,1,2,1;

%e   0,0,1,2,1;

%e   0,0,0,1,2,1;

%e   0,0,0,0,1,2,1;

%e   0,0,0,0,0,1,2,1;

%e   0,0,0,0,0,0,1,2,1;

%e   0,0,0,0,0,0,0,1,2,1;

%e   0,0,0,0,0,0,0,0,1,2,1;

%e   ...

%t Array[PadLeft[{1, 2, 1}, #] &,15] (* _Paolo Xausa_, Jun 27 2024 *)

%Y Cf. A004736, A130713, A185018.

%K nonn,tabl

%O 1,2

%A _Mats Granvik_, Oct 30 2009