|
%I #13 Sep 25 2017 07:50:14
%S 1,3,6,15,21,28,36,66,78,91,105,120,190,210,231,253,276,300,435,465,
%T 496,528,561,595,630,861,903,946,990,1035,1081,1128,1176,1540,1596,
%U 1653,1711,1770,1830,1891,1953,2016,2556,2628,2701,2775,2850,2926,3003,3081,3160,3240
%N Take 3 triangle numbers, skip 1 triangle number, take 4 triangle numbers, skip 2 triangle numbers, take 5 triangle numbers, skip 3 triangle numbers, ...
%H Seiichi Manyama, <a href="/A292610/b292610.txt">Table of n, a(n) for n = 1..10000</a>
%t 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 *)
%Y Cf. A000217, A222716, A292611.
%K nonn
%O 1,2
%A _Seiichi Manyama_, Sep 20 2017
|
