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”).

Triangle read by rows: T(n,k) = 1 iff 2 divides binomial(n,k) but 4 does not (0 <= k <= n).
1

%I #22 Aug 21 2021 01:00:00

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

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

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

%N Triangle read by rows: T(n,k) = 1 iff 2 divides binomial(n,k) but 4 does not (0 <= k <= n).

%H P. Goetgheluck, <a href="https://www.jstor.org/stable/2323099">Computing binomial coefficients</a>, The American Mathematical Monthly 94.4 (1987): 360-365. See Fig. 2.

%e Triangle begins:

%e 0,

%e 0, 0,

%e 0, 1, 0,

%e 0, 0, 0, 0,

%e 0, 0, 1, 0, 0,

%e 0, 0, 1, 1, 0, 0,

%e 0, 1, 0, 0, 0, 1, 0,

%e 0, 0, 0, 0, 0, 0, 0, 0,

%e 0, 0, 0, 0, 1, 0, 0, 0, 0,

%e 0, 0, 0, 0, 1, 1, 0, 0, 0, 0,

%e 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0,

%e 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0,

%e 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,

%e ...

%Y Cf. A007318, A007814, A047999, A346619.

%K nonn,tabl

%O 0

%A _N. J. A. Sloane_, Aug 21 2021