A279647 - OEIS

%I #19 Nov 01 2021 03:14:21

%S 0,0,0,1,2,4,0,2,3,4,5,6,7,9,10,0,3,4,5,6,7,9,10,11,12,13,14,15,16,17,

%T 18,20,0,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,20,21,22,23,24,25,26,

%U 27,28,29,30,31,32,33,34

%N Irregular triangle read by rows: possible numbers of the diagonals of an n-faced convex polyhedron.

%e Triangle begins:

%e 4 | 0;

%e 5 | 0;

%e 6 | 0, 1, 2, 4;

%e 7 | 0, 2, 3, 4, 5, 6, 7,  9, 10;

%e 8 | 0, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20;

%Y Cf. A279015, A279019, A279022, A279620, A279679, A279681.

%K nonn,tabf,more

%O 4,5

%A _Vladimir Letsko_, Dec 16 2016