23801

Properties

Appears in sequences

• G.f.: (1 + x^4 + x^7 + 2*x^8 + x^9 + x^12 + x^16)/Product_{i=1..8} (1 - x^i).at n=38A003405
• Primes p such that 1 + product of primes up to p is prime.at n=16A005234
• Least prime in A031930 (lesser of 12-twins) whose distance to the next 12-twin is 2*n.at n=22A052355
• Primes p such that p-12, p and p+12 are consecutive primes.at n=24A053072
• Primes p for which the period of reciprocal = (p-1)/8.at n=36A056213
• Generalized Somos-7 sequence: a(n)*a(n+7) = 3*a(n+1)*a(n+6) - 4*a(n+2)* a(n+5) + 4*a(n+3)*a(n+4).at n=14A058058
• Square array read by antidiagonals: T(n,k) = (k*(2*k+3)^n + 1)/(k+1).at n=49A083075
• 6th row of number array A083075.at n=4A083078
• First subdiagonal of number array A083075.at n=4A083082
• Maximum value taken on by f(P) = Sum_{i=1..n} p(i)*p(n+1-i) as {p(1),p(2),...,p(n)} ranges over all permutations P of {1,2,3,...,n}.at n=41A087035
• Number of permutations of length n which avoid the patterns 2341, 4132, 4321.at n=9A116836
• a(n) = Sum_{k=1..n} k*sigma(k).at n=34A143128
• Primes that become squares when prefixed with a 4.at n=2A167737
• Number of arrays of -7..7 integers x(1..n) with every x(i) in a subsequence of length 1 or 2 with sum zero.at n=6A193647
• Centered 40-gonal numbers.at n=34A195317
• Primes of the form 5*k^2 - 4.at n=18A201786
• Primes that are the sum of three consecutive primes in A034962.at n=36A207527
• Balanced primes which are the average of two successive semiprimes.at n=21A212820
• a(n) = 139*n^2 - 2307*n + 3331.at n=23A230307
• Primes of the form (p+q)^2 + pq, where p and q are consecutive primes.at n=10A252231