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

105, 120, 136, 153, 171, 190, 231, 253, 276, 300, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 703, 780, 820, 861, 903, 946, 990, 1596, 1711, 2145, 2346, 3240, 3321, 3486, 3570, 3741, 4371, 4560, 4753, 5565

Offset

1,1

Comments

The number 496 appears to be the unique perfect number A000396 of this sequence. The interesting numbers 120 and 153 are supertriangular numbers.

Links

Table of n, a(n) for n=1..40.

Example

The numbers 120 as a triangle-shaped number A134999:
. 2 .
1 . .
. . 0
The number 120 as a triangular number A000217:
. . . . . . . O
. . . . . . .O O
. . . . . . O O O
. . . . . .O O O O
. . . . . O O O O O
. . . . .O O O O O O
. . . . O O O O O O O
. . . .O O O O O O O O
. . . O O O O O O O O O
. . .O O O O O O O O O O
. . O O O O O O O O O O O
. .O O O O O O O O O O O O
. O O O O O O O O O O O O O
.O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O <--- A000217(15)=120.

Crossrefs

Cf. A000217, A000396, A134999, A135600, A135601, A135602, A135603, A135643.

Sequence in context: A096093 A179142 A039553 * A162304 A033268 A325903

Adjacent sequences: A135996 A135997 A135998 * A136000 A136001 A136002

Keyword

base,nonn

Author

Omar E. Pol, Dec 10 2007

Status

approved