38327

Properties

Appears in sequences

• All 81 combinations of prefixing and following a(n) by a single digit are nonprime.at n=26A032734
• a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes allowed).at n=5A032736
• a(1) = 1; a(n) = a(n-1) + sigma(a(n-1)) where sigma(k) = sum of the divisors of k.at n=14A081973
• Primes from merging of 5 successive digits in decimal expansion of Pi.at n=3A104825
• Irregular array where row n is the positive integers which divide the sum of all previous rows. a(1,1)=1.at n=43A119763
• List of strictly non-palindromic twin primes {p, p+2}.at n=18A138329
• Lesser of twin primes such that both twin primes have no bases b, 1 < b < p-1, in which p is a palindrome.at n=9A138348
• Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard symmetric under 180 degree rotation.at n=8A143874
• Lesser of twin primes p such that 6*p+1 is greater of twin primes.at n=17A176131
• Number of lower triangles of a 3 X 3 0..n array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by two or less.at n=37A195249
• Primes of the form 7n^2 - 5.at n=15A201851
• a(n) = prime(k+1) with k = n^2 + prime(n)^2.at n=17A243894
• Primes p such that q1=6*p-1 and q2=6*p+1 are also primes (twin primes) and q1 is a Sophie Germain prime (i.e., 2*q1+1 is prime).at n=28A358381
• Twin primes p such that 6p+1, 6p-1 is a twin prime pair.at n=36A386724
• Number of integer compositions of n that (1) have all parts > 1 and (2) are not the first sums of any finite nonnegative sequence.at n=25A391679
• Prime numbersat n=4046