666435

Appears in sequences

• Triangular numbers such that both the number formed by the first floor((k+1)/2) digits and the remaining part (if any) are triangular numbers, where k is the number of digits.at n=22A068821
• Triangular numbers t such that t - 4, t - 2, t + 2, t + 4 are four primes.at n=4A226109
• Smallest triangular numbers whose decimal expansion begins (nontrivially) with n-th triangular number.at n=35A229235