30661

Properties

Appears in sequences

• Prime number spiral (clockwise, Northeast spoke).at n=29A054553
• Numbers k such that A048138(k) is a prime and sets a new record for such primes.at n=40A064440
• Numbers k such that k, k+1, k+2 and k+3 are 1,2,3,4-almost primes.at n=26A113000
• Largest prime < 10*a(n-1), a(1)=31.at n=3A124335
• Primes of the form 2*n^2 + 54*n + 25.at n=9A217497
• Primes p of the form 420k + 1 for some k.at n=29A217587
• Primes formed from concatenation of PrimePi(n) and prime(n).at n=37A236551
• Primes p such that Sum_{k=primes<p} (k mod p) and Sum_{k=primes<p} (p mod k) are both prime.at n=15A274025
• a(n) is the smallest prime p such that there is a multiplicative subgroup H of Z/pZ, of odd order and of index 2n, such that for any two cosets H1 and H2 of H, H1 + H2 contains all of (Z/pZ)\0, except that H+H contains all of (Z/pZ)\0 except -H. If no such prime exists, a(n) = 0.at n=29A294615
• Terms k of A112998 such that k+2 is nonsquarefree.at n=21A328160
• Numbers m such that numbers m, m + 1, m + 2 and m + 3 have k, 2k, 3k and 4k divisors respectively.at n=19A340157
• Primes p such that p, p + 1, p + 2 and p + 3 have 2, 4, 6 and 8 divisors respectively.at n=1A340871
• Emirps p such that if q is the next emirp after p, 2*q-p is also an emirp.at n=29A350852
• Prime numbersat n=3307