208981domain: NAppears in sequencesa(n) = (n^2-1)*(2*n^2-1).at n=18A033595a(1) = 0, then smallest triangular number such that a(n+1)- a(n) is a palindrome.at n=34A075057Concatenation of triangular number k and its 10's complement is prime.at n=33A108970Triangular numbers T such that T+10 is the next prime after T.at n=29A129540