351541

Appears in sequences

• Lexicographically earliest sequence of pairwise coprime triangular numbers.at n=34A034792
• Triangular numbers such that the product of digits is also a (positive) triangular number.at n=30A069077
• Smallest triangular number beginning with the n-th triangular number other than itself.at n=25A072517
• Triangular numbers that are also brilliant (A078972).at n=33A113940
• Product p*q of two primes with q = 2*p + 1.at n=21A156592
• Semiprimes of form p*q with p < q, such that 2^p - 1 == 0 (mod q).at n=27A179768
• Triangular numbers representable as triangular(x)*triangular(y)+1.at n=25A226389
• Smallest triangular numbers whose decimal expansion begins (nontrivially) with n-th triangular number.at n=25A229235
• Numbers n such that A229964(n) = 1.at n=24A229965
• Squarefree numbers (from A005117) with prime divisors in a 2p+1 progression.at n=27A231966
• Numbers n with the property that the symmetric representation of sigma(n) has four parts, each of width one and two regions meet at the center of the Dyck path.at n=39A264104
• T(n,k)=Number of nXk 0..2 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.at n=37A280673
• Number of 2 X n 0..2 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.at n=7A280674
• Triangular numbers that are the product of two distinct prime numbers of the form 4*k + 3.at n=10A365849
• Triangular numbers that are emirpimes.at n=13A375385