28233

Appears in sequences

• Numbers k such that the concatenation of k with k-8 gives a square.at n=5A115435
• Numbers k such that k concatenated with k-9 gives the product of two numbers which differ by 2.at n=5A116095
• a(n) = number of strings of length n that can be obtained by starting with abc and repeatedly doubling any substring of length >= 2 in place.at n=37A135156
• Number of different strings of length n+6 obtained from "123...n" by iteratively duplicating any substring.at n=9A137739
• Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 01000-11100-00111-00010 pattern in any orientation.at n=19A147335
• a(n) = smallest composite (odd) number greater than a(n-1) such that a(n)+2n is the first prime after a(n).at n=21A189118
• Integers n such that 6 * 7^n + 1 is prime.at n=9A245241
• Numbers k such that (238*10^k - 1)/3 is prime.at n=26A273542