23633

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 13.at n=18A031601
• Numbers k such that k-1 is a palindrome in base 10, and k+1 is a palindrome in base 17.at n=21A033621
• Triangle: a(n,m) = number of permutations of (1,2,...,n) with one or more fixed points in the m first positions.at n=34A061018
• Primes arising as the 10's complement of A109862(n).at n=25A109863
• Primes that are the difference of two Lucas numbers; primes in A113191.at n=26A113192
• Primes p=prime(i) of level (1,5), i.e., such that A118534(i) = prime(i-5).at n=1A118464
• Primes p such that q-p = 30, where q is the next prime after p.at n=26A124596
• Primes p such that p^3 +- (p+1) are primes.at n=27A137472
• a(n) is n-th prime == -1 (mod 6n).at n=38A138905
• Primes congruent to 26 mod 61.at n=37A142824
• Primes p of the form 4*k+1 for which s=26 is the least positive integer such that s*p-(floor(sqrt(s*p)))^2 is a square.at n=34A145050
• Smallest primes p = p(k) with (p(k)+p(k+1)+p(k+2))/15 an integer.at n=19A168556
• Primes p such that 3*p+2, 5*p+4 and 7*p+6 are also prime.at n=24A173876
• Primes with exactly three 3's.at n=25A178552
• Triangle read by rows: T(n,k) is the number of permutations p of [n] for which k is the smallest among the positive differences p(i+1) - p(i); k=0 for the reversal of the identity permutation (0<=k<=n-1).at n=29A180190
• Number of permutations of [n] having at least one succession. A succession of a permutation p is a position i such that p(i+1)-p(i) = 1.at n=7A180191
• Primes of the form 7k^3+8.at n=2A201256
• Fibonacci sequence beginning 11, 8.at n=17A206420
• Find the first (maximal) string of consecutive primes of length exactly n which alternate between 4*k+1 and 4*k+3 or 4*k+3 and 4*k+1 as in A002144(4*n+1) and A002145(4*n+3). The first element is a(n).at n=9A247384
• Primes p such that both (p^2 + 5)/6 and (p^4 + 5)/6 are prime.at n=18A253925