a(n) is the index of the smallest triangular number containing exactly n 9's.
A048364
a(n) is the index of the smallest triangular number containing exactly n 9's.
Terms
- a(0) =13a(1) =44a(2) =631a(3) =1413a(4) =28282a(5) =76419a(6) =282842a(7) =1414213a(8) =4471955a(9) =31616419a(10) =446313656a(11) =1414001413a(12) =6276925986a(13) =44710913656a(14) =44721356419a(15) =632129732586a(16) =527257052109
External references
- oeis: A048364