84666

Appears in sequences

• Numbers of the form prime(n) + prime(n+1) - 2 that are also triangular numbers, T(k) = k(k+1)/2.at n=31A110891
• Triangular numbers all of whose digits are nonprimes.at n=37A111484
• Triangular numbers with only even digits.at n=16A117978
• Triangular numbers composed of digits {4,6,8}.at n=4A119212
• Smallest triangular number whose decimal expansion ends (nontrivially) with the n-th triangular number.at n=35A229262
• Numbers that start a run of four consecutive triangular numbers with four distinct prime factors.at n=16A349773
• Indices of the Sylvester primes (A375543) in the primes (A000040).at n=40A375545
• Hexagonal numbers that are products of exactly four distinct primes.at n=36A381920