73153

Appears in sequences

• Lexicographically earliest sequence of pairwise coprime triangular numbers.at n=17A034792
• Triangular numbers which are the product of two primes.at n=24A068443
• Triangular numbers that are also brilliant (A078972).at n=17A113940
• Triangular numbers that are the product of 2 palindromes greater than 1.at n=36A115744
• Triangular numbers with only odd digits.at n=23A117960
• Semiprimes in A006987(n), or semiprime binomial coefficients: C(n,k), 2 <= k <= n-2.at n=25A124000
• Product p*q of two primes with q = 2*p + 1.at n=14A156592
• Triangular numbers t such that all the digits needed to write the consecutive triangular numbers from 0 to t fill exactly an equilateral triangle (no holes, no overlaps).at n=23A158030
• a(n) = (3*2^(n-1)-1)*(3*2^n-1).at n=7A169720
• Semiprimes of form p*q with p < q, such that 2^p - 1 == 0 (mod q).at n=16A179768
• Primitive numbers in A229307.at n=35A229311
• Numbers n such that A229964(n) = 1.at n=17A229965
• Squarefree numbers (from A005117) with prime divisors in a 2p+1 progression.at n=19A231966
• 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=23A264104
• Triangular numbers such that the sum of cubes of their digits is prime.at n=32A345351
• Least odd number m such that m*2^n is an amicable number, and -1 if no such number exists.at n=7A358022
• Triangular numbers that are the product of two distinct prime numbers of the form 4*k + 3.at n=6A365849
• Triangular numbers that are emirpimes.at n=7A375385