cp's OEIS Frontend

A132169 Irregular triangle read by rows. A141616(n)/4.

%I A132169 #25 Jul 20 2020 13:05:04
%S A132169 2,3,6,4,8,5,12,10,6,15,12,7,20,18,14,8,24,21,16,9,30,28,24,18,10,35,
%T A132169 32,27,20,11,42,40,36,30,22,12,48,45,40,33,24,13,56,54,50,44,36,26,14,
%U A132169 63,60,55,48,39,28,15,72,70,66,60,52,42,30,16
%N A132169 Irregular triangle read by rows. A141616(n)/4.
%C A132169 From _Paul Curtz_, Apr 14 2016: (Start)
%C A132169 Row sums: A023856.
%C A132169 Even rows: A120070.
%C A132169 Odd rows:
%C A132169 2,
%C A132169 6,   4,
%C A132169 12, 10, 6,
%C A132169 etc.
%C A132169 Divided by 2:
%C A132169 1,
%C A132169 3,   2,
%C A132169 6,   5,  3,
%C A132169 10,  9,  7, 4,
%C A132169 15, 14, 12, 9, 5,
%C A132169 etc.
%C A132169 This is A049777. Or positive A049780.
%C A132169 Also A271668 without the first column and bordered by the natural numbers as main diagonal.
%C A132169 (End)
%e A132169 Irregular triangle:
%e A132169 2,
%e A132169 3,
%e A132169 6,   4,
%e A132169 8,   5,
%e A132169 12, 10, 6,
%e A132169 15, 12, 7,
%e A132169 20, 18, 14,  8,
%e A132169 24, 21, 16,  9,
%e A132169 30, 28, 24, 18, 10,
%e A132169 35, 32, 27, 20, 11,
%e A132169 etc.
%t A132169 (Table[n^2 - k^2, {n, 3, 18}, {k, n}] /. m_ /; Or[OddQ@ m, m == 0] -> Nothing)/4 // Flatten (* _Michael De Vlieger_, Apr 14 2016 *)
%Y A132169 Cf. A023856, A049777, A049780, A052938, A120070, A131723, A141616, A168230, A198442, A271668.
%K A132169 nonn,tabf
%O A132169 0,1
%A A132169 _Paul Curtz_, Aug 26 2008
%E A132169 Edited by _Charles R Greathouse IV_, Nov 11 2009