cp's OEIS Frontend

A135999 Numbers that are both triangular numbers A000217 and triangle-shaped numbers A134999.

%I A135999 #2 Mar 30 2012 17:33:53
%S A135999 105,120,136,153,171,190,231,253,276,300,325,351,378,406,435,465,496,
%T A135999 528,561,595,703,780,820,861,903,946,990,1596,1711,2145,2346,3240,
%U A135999 3321,3486,3570,3741,4371,4560,4753,5565
%N A135999 Numbers that are both triangular numbers A000217 and triangle-shaped numbers A134999.
%C A135999 The number 496 appears to be the unique perfect number A000396 of this sequence. The interesting numbers 120 and 153 are supertriangular numbers.
%e A135999 The numbers 120 as a triangle-shaped number A134999:
%e A135999 . 2 .
%e A135999 1 . .
%e A135999 . . 0
%e A135999 The number 120 as a triangular number A000217:
%e A135999 . . . . . . . O
%e A135999 . . . . . . .O O
%e A135999 . . . . . . O O O
%e A135999 . . . . . .O O O O
%e A135999 . . . . . O O O O O
%e A135999 . . . . .O O O O O O
%e A135999 . . . . O O O O O O O
%e A135999 . . . .O O O O O O O O
%e A135999 . . . O O O O O O O O O
%e A135999 . . .O O O O O O O O O O
%e A135999 . . O O O O O O O O O O O
%e A135999 . .O O O O O O O O O O O O
%e A135999 . O O O O O O O O O O O O O
%e A135999 .O O O O O O O O O O O O O O
%e A135999 O O O O O O O O O O O O O O O <--- A000217(15)=120.
%Y A135999 Cf. A000217, A000396, A134999, A135600, A135601, A135602, A135603, A135643.
%K A135999 base,nonn
%O A135999 1,1
%A A135999 _Omar E. Pol_, Dec 10 2007