50821

Properties

Appears in sequences

• Indices of primes at which the prime race 4k-1 vs. 4k+1 is tied.at n=34A038691
• Centered heptagonal prime numbers.at n=27A144974
• Prime numbers whose central digit equals the sum of the other digits.at n=31A235119
• Terms k of A112998 such that k+2 is nonsquarefree.at n=27A328160
• Numbers m such that numbers m, m + 1, m + 2 and m + 3 have k, 2k, 3k and 4k divisors respectively.at n=29A340157
• The number of regions inside a concave circular triangle formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.at n=18A340685
• Primes p such that p, p + 1, p + 2 and p + 3 have 2, 4, 6 and 8 divisors respectively.at n=2A340871
• Numbers k such that d(k) < d(k+1) < d(k+2) < d(k+3) < d(k+4), where d(n) is the number of divisors of n.at n=6A364717
• The n-th term of the sequence is the last term of n's trajectory under the "multiply with zero" rules explained in A365993.at n=9A365994
• Prime numbersat n=5205