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A292610
Take 3 triangle numbers, skip 1 triangle number, take 4 triangle numbers, skip 2 triangle numbers, take 5 triangle numbers, skip 3 triangle numbers, ...
3
1, 3, 6, 15, 21, 28, 36, 66, 78, 91, 105, 120, 190, 210, 231, 253, 276, 300, 435, 465, 496, 528, 561, 595, 630, 861, 903, 946, 990, 1035, 1081, 1128, 1176, 1540, 1596, 1653, 1711, 1770, 1830, 1891, 1953, 2016, 2556, 2628, 2701, 2775, 2850, 2926, 3003, 3081, 3160, 3240
OFFSET
1,2
LINKS
MATHEMATICA
Block[{s = Array[{# + 2, #} &, 8], r}, r = PolygonalNumber@ Range@ Total@ Flatten@ s; Map[Function[{a, b}, {First@ #, Set[r, Drop[Last@ #, b]]} &@ TakeDrop[r, a]] @@ # &, s][[All, 1]] // Flatten] (* Michael De Vlieger, Sep 25 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 20 2017
STATUS
approved