21467

Properties

Appears in sequences

• Convolution of Fibonacci numbers and primes.at n=16A023615
• Primes of the form k^2 + k + 5.at n=38A027755
• Least prime in A031932 (lesser of 14-twins) whose distance to the next 14-twin is 6*n.at n=3A052356
• Second term p(m) of strong prime sextets: p(m)-p(m-1) > p(m+1)-p(m) > p(m+2)-p(m+1) > p(m+3)-p(m+2) > p(m+4)-p(m+3).at n=4A054814
• Sixth term of weak prime sextet: p(m-4)-p(m-5) < p(m-3)-p(m-4) < p(m-2)-p(m-3) < p(m-1)-p(m-2) < p(m)-p(m-1).at n=6A054833
• Group the natural numbers such that the n-th group contains n terms and the group sum is the smallest possible prime: (2), (1, 4), (3, 5, 9), (6, 7, 8, 10), (11, 12, 13, 14, 17), (15, 16, 18, 19, 20, 21), ... Sequence gives group sums.at n=34A075345
• Prime means of 12 horizontal, vertical and main diagonal sums associated with primes in A094458.at n=10A094459
• Primes prime(k) such that (prime(k-1) + prime(k+1) + prime(k+2))/prime(k) = 3.at n=36A094933
• Primes p such that the largest prime factor of p^5 + 1 is less than p.at n=6A102327
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, 0), (0, 1, -1), (1, 0, -1), (1, 1, 1)}.at n=8A149687
• Primes p such that all the digits needed to write the consecutive Primes from 2 to p fill exactly a square (no holes, no overlaps).at n=27A158024
• Row sums of the triangle in A162371.at n=34A162373
• Primes p of the form p = prime(n) + prime(n+1) - 5 and p = prime(k) + prime(k+1) + 5.at n=40A207992
• Prime numbers after which at least four distinct classes modulo 7 are equally represented among the primes to that point.at n=24A217147
• Tenth prime p such that (p+n)^2+n is prime but (p+j)^2+j is not prime for all 0<j<n.at n=36A238682
• The number of conjugacy classes of invertible n X n matrices over GF(2) which are squares of other such matrices.at n=15A266462
• a(n) is the least prime p such that p+prime(n) has exactly n prime factors, counted with multiplicity.at n=11A332860
• Primes which, when added to their reversals, produce palindromic primes.at n=18A342681
• Number of partitions of n with exactly five part sizes.at n=27A365631
• Last prime in n-th run of successive primes in A375564.at n=12A376197