Numbers n such that A002113(n) is a triangular number.

Terms

a(0) =0a(1) =1a(2) =3a(3) =6a(4) =14a(5) =15a(6) =26a(7) =68a(8) =75a(9) =129a(10) =158a(11) =186a(12) =249a(13) =759a(14) =1616a(15) =1827a(16) =2268a(17) =2679a(18) =4543a(19) =6072a(20) =6675a(21) =7294a(22) =13512a(23) =16146a(24) =27871a(25) =112640a(26) =116339a(27) =152889a(28) =161727a(29) =239533