%I #21 Jul 11 2022 17:01:55
%S 4,0,2,6,0,2,4,6,4,0,2,4,8,4,8,4,2,0,0,2,4,10,6,12,8,8,6,6,0,2,0,0,0,
%T 0,0,0,2,4,12,8,16,14,16,12,12,12,6,4,8,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,
%U 0,0,0,0,0,2,4,14,10,20,22,24,22,22,26,18,16,12,16,12,0,4,10,0
%N Triangle T(n,k) = number of binary n-tuples u having exactly k grandchildren, where a grandchild is a vector obtained by deleting any two coordinates of u (n >= 2, 0<=k<=2^(n-2)).
%C Row sums = 2^n. - _Sean A. Irvine_, Jun 20 2022
%D N. J. A. Sloane, On single-deletion-correcting codes, in Codes and Designs (Columbus, OH, 2000), 273-291, Ohio State Univ. Math. Res. Inst. Publ., 10, de Gruyter, Berlin, 2002.
%H Reinhard Zumkeller, <a href="/A057607/b057607.txt">Table of n, a(n) for n = 2..16397</a> [a(2) changed by Georg Fischer, Jul 11 2022]
%H N. J. A. Sloane, <a href="http://neilsloane.com/doc/dijen.txt">On single-deletion-correcting codes</a>
%e Triangle begins:
%e 4;
%e 0,2,6;
%e 0,2,4,6,4;
%e 0,2,4,8,4,8,4,2,0;
%e ...
%e a(2)=4 because each of 00, 01, 10, 11, leaves no grandchildren. - _Sean A. Irvine_, Jun 20 2022
%o (Haskell)
%o a057607 n k = a057607_tabf !! (n-2) !! k
%o a057607_row n = a057607_tabf !! (n-2)
%o a057607_tabf = [4] : map (0 :) a057606_tabf
%o -- _Reinhard Zumkeller_, Apr 30 2012
%Y Cf. A057606.
%K nonn,tabf,nice
%O 2,1
%A _N. J. A. Sloane_, Oct 08 2000
%E a(2) corrected by _Sean A. Irvine_, Jun 20 2022