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A135999
Numbers that are both triangular numbers A000217 and triangle-shaped numbers A134999.
0
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.
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.
KEYWORD
base,nonn
AUTHOR
Omar E. Pol, Dec 10 2007
STATUS
approved