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A278645
Triangle read by rows in which each new term is the sum of its two largest neighbors in the structure.
2
1, 1, 2, 3, 5, 7, 8, 15, 22, 29, 23, 45, 74, 103, 132, 68, 142, 245, 377, 509, 641, 210, 455, 832, 1341, 1982, 2623, 3264, 665, 1497, 2838, 4820, 7443, 10707, 13971, 17235, 2162, 5000, 9820, 17263, 27970, 41941, 59176, 76411, 93646, 7162, 16982, 34245, 62215, 104156, 163332, 239743, 333389, 427035, 520681
OFFSET
1,3
COMMENTS
To evaluate T(n,k) consider only the two largest neighbors of T(n,k) that are present in the triangle when T(n,k) should be a new term in the triangle.
For the same idea but for a square spiral see A278180; and for a hexagonal spiral see A278619.
It appears that the same idea for an isosceles triangle and also for a square array gives A030237.
EXAMPLE
Triangle begins:
1;
1, 2;
3, 5, 7;
8, 15, 22, 29;
23, 45, 74, 103, 132;
68, 142, 245, 377, 509, 641;
210, 455, 832, 1341, 1982, 2623, 3264;
665, 1497, 2838, 4820, 7443, 10707, 13971, 17235;
2162, 5000, 9820, 17263, 27970, 41941, 59176, 76411, 93646;
7162, 16982, 34245, 62215, 104156, 163332, 239743, 333389, 427035, 520681;
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Omar E. Pol, Nov 24 2016
STATUS
approved