Numbers k such that 21 plus the k-th triangular number is a perfect square.

A154148

Numbers k such that 21 plus the k-th triangular number is a perfect square.

Terms

    a(0) =5a(1) =7a(2) =40a(3) =50a(4) =237a(5) =295a(6) =1384a(7) =1722a(8) =8069a(9) =10039a(10) =47032a(11) =58514a(12) =274125a(13) =341047a(14) =1597720a(15) =1987770a(16) =9312197a(17) =11585575a(18) =54275464a(19) =67525682

External references