23203

Properties

Appears in sequences

• Number of achiral rooted trees.at n=28A003241
• Discriminants of imaginary quadratic fields with class number 19 (negated).at n=39A046016
• Primes p from A031924 such that A052180(p) = 23.at n=18A052238
• n is prime and is the concatenation of numbers n_1, n_2, n_3, in that order, with n_1 - n_2 = n_3. (Do not allow leading zeros for nonzero n_i.)at n=24A067861
• Largest prime factor of 3^n+2.at n=18A080443
• Number of nonempty subsets S of {1,2,3,...,n} that have the property that no element x of S is a nonnegative integer linear combination of elements of S-{x}.at n=24A103580
• Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1010-1111 pattern in any orientation.at n=16A146811
• Primes p such that the multiplicative order of 2 modulo p is (p-1)/9.at n=16A152309
• Primes p with P(p-1) also prime, where P(.) is the partition function (A000041).at n=21A234569
• Prime numbers P such that 8*P^2-1 and 8*(8*P^2-1)^2-1 are also prime numbers.at n=37A245674
• Number of n X 5 nonnegative integer arrays with upper left 0 and lower right n+5-4 and value increasing by 0 or 1 with every step right or down.at n=5A252873
• Number of n X 6 nonnegative integer arrays with upper left 0 and lower right n+6-4 and value increasing by 0 or 1 with every step right or down.at n=4A252874
• T(n,k) = Number of n X k nonnegative integer arrays with upper left 0 and lower right n+k-4 and value increasing by 0 or 1 with every step right or down.at n=49A252876
• T(n,k) = Number of n X k nonnegative integer arrays with upper left 0 and lower right n+k-4 and value increasing by 0 or 1 with every step right or down.at n=50A252876
• Primes p such that each decimal digit of p is equal to the difference of two other digits of p.at n=16A255892
• Primes having only {0, 2, 3} as digits.at n=18A260125
• Number of nX3 0..1 arrays with every element unequal to 1, 2, 3, 6 or 7 king-move adjacent elements, with upper left element zero.at n=9A305084
• Numbers k such that 327*2^k+1 is prime.at n=23A322956
• Numbers with decimal expansion d_1, ..., d_w such that for any k in 1..w there is some m in 1..w such that d_k = d_m = abs(k - m).at n=23A336880
• Primes p such that p, x+y, x-y, p-x*y and p+x*y are prime, where y = p mod 5 and x = (p-y)/5.at n=24A342771