cp's OEIS Frontend

A080382 Triangle read by rows: T(n,k) = C(n,floor(n/2))/gcd(C(n,floor(n/2)),C(n,k)), k=0..n; central binomial coefficient is divided by greatest common divisor of binomial coefficients and corresponding central binomial coefficient.

%I A080382 #11 Oct 27 2019 05:17:00
%S A080382 1,1,1,2,1,2,3,1,1,3,6,3,1,3,6,10,2,1,1,2,10,20,10,4,1,4,10,20,35,5,5,
%T A080382 1,1,5,5,35,70,35,5,5,1,5,5,35,70,126,14,7,3,1,1,3,7,14,126,252,126,
%U A080382 28,21,6,1,6,21,28,126,252,462,42,42,14,7,1,1,7,14,42,42,462,924,77,14,21,28
%N A080382 Triangle read by rows: T(n,k) = C(n,floor(n/2))/gcd(C(n,floor(n/2)),C(n,k)), k=0..n; central binomial coefficient is divided by greatest common divisor of binomial coefficients and corresponding central binomial coefficient.
%e A080382 Triangle begins:
%e A080382    1;
%e A080382    1,  1;
%e A080382    2,  1,  2;
%e A080382    3,  1,  1,  3;
%e A080382    6,  3,  1,  3,  6;
%e A080382   10,  2,  1,  1,  2, 10;
%e A080382   20, 10,  4,  1,  4, 10, 20;
%e A080382   35,  5,  5,  1,  1,  5,  5, 35;
%t A080382 Table[Table[Binomial[n, Floor[n/2]]/GCD[Binomial[n, j], Binomial[n, Floor[n/2]]], {j, 0, n}], {n, 1, 10}]
%Y A080382 Cf. A007318, A001405, A080381.
%K A080382 nonn,tabl
%O A080382 1,4
%A A080382 _Labos Elemer_, Mar 12 2003