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, ...

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

Author

Seiichi Manyama, Sep 20 2017

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000217, A222716, A292611.

Programs

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 *)