231540

Appears in sequences

• Triangular numbers whose digits can be rearranged to form a substring of 123456789012345678901234....at n=21A068804
• Smallest triangular number beginning with the n-th triangular number other than itself.at n=20A072517
• Least triangular number whose digits include a permutation of {0,1,...,n}.at n=5A111482
• Triangular numbers that are sums of twin prime pairs.at n=23A165966
• Triangular numbers which are sums of 4 consecutive primes.at n=18A173420
• Smallest triangular numbers whose decimal expansion begins (nontrivially) with n-th triangular number.at n=20A229235
• Triangular numbers which have one or more occurrences of exactly six different digits.at n=31A241789
• Triangular numbers with tetrahedral indices: a(n) = (1/72) * (n*(n+1)*(n+2)*(n+3)*(n^2+2)).at n=15A373733