60031
domain: N
Appears in sequences
- Lexicographically earliest sequence of pairwise coprime triangular numbers.at n=16A034792
- Triangular numbers with every digit a triangular number.at n=16A062100
- Triangular numbers with sum of digits = 10.at n=33A068129
- Triangular numbers which are the product of two primes.at n=22A068443
- Triangular numbers whose digit permutations yield at least two further triangular numbers.at n=32A069674
- Triangular number x such that x + reverse of x is a prime.at n=16A072387
- Triangular numbers whose sum of aliquot divisors is a prime number.at n=27A083676
- Triangular numbers that are also brilliant (A078972).at n=15A113940
- Semiprimes in A006987(n), or semiprime binomial coefficients: C(n,k), 2 <= k <= n-2.at n=23A124000
- Product p*q of two primes with q = 2*p + 1.at n=12A156592
- a(n) = A185128(n) + A185129(n).at n=8A185243
- Triangular numbers which are an average of four consecutive primes.at n=30A226196
- Primitive numbers in A229307.at n=32A229311
- Numbers n such that A229964(n) = 1.at n=15A229965
- Triangular numbers representable as b! + c^2.at n=36A230364
- Squarefree numbers (from A005117) with prime divisors in a 2p+1 progression.at n=17A231966
- Triangular numbers n with digits d_1, d_2, ..., d_k such that d_1*(d_1+1)/2 + ... + d_k*(d_k+1)/2 is a triangular number.at n=39A254957
- 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=21A264104
- Integers k such that k + 1 has a divisor that is an anagram of k, which must have the same number of digits as k.at n=18A384597