Powerful(1) numbers (A001694) whose digit reversal is a triangular number.

Terms

a(0) =1a(1) =100a(2) =1000a(3) =5400a(4) =10000a(5) =54000a(6) =100000a(7) =540000a(8) =1000000a(9) =1306449a(10) =1728243a(11) =5400000a(12) =10000000a(13) =50086125a(14) =54000000a(15) =100000000a(16) =130644900a(17) =172824300a(18) =540000000a(19) =1000000000a(20) =1044000721a(21) =1306449000a(22) =1728243000a(23) =5008612500