21525

Appears in sequences

• Base-8 palindromes that start with 5.at n=34A043025
• Total area of all polyominoes with perimeter 2n.at n=7A057753
• Number of permutations of n distinct letters (ABCD...) each of which appears 5 times and having n-2 fixed points.at n=41A123296
• Numbers k such that binomial(6k, k) + 1 is prime.at n=21A125245
• a(1) = 1. a(n) = the smallest positive multiple of a(n-1) with exactly n 1's in its binary representation.at n=5A140451
• a(n) is the smallest positive multiple of 2n-1 that contains the binary representation of n in its binary representation and that is a palindrome when written in binary.at n=20A158789
• Numbers n palindromic in exactly three bases b, 2 <= b <= 10.at n=45A214425
• Palindromic numbers in bases 2 and 8 written in base 10.at n=45A259380
• Palindromic numbers in bases 4 and 8 written in base 10.at n=43A259382
• Coordination sequence for (2,5,8) tiling of hyperbolic plane.at n=22A265067
• If n^2 has an even number of digits, write n after the left half of the digits of n^2 and before the right half, otherwise if n^2 has 2t+1 digits, write n after the first t digits of n^2 and before the last t+1 digits.at n=14A274620
• Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 137", based on the 5-celled von Neumann neighborhood.at n=14A279143
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 137", based on the 5-celled von Neumann neighborhood.at n=14A279144
• Numbers that are palindromic in bases 2, 4, and 8.at n=16A319584
• Odd composites for which gcd(A325977(n), A325978(n)) is equal to abs(A325977(n)).at n=7A325981
• Positive numbers k such that the binary and negabinary representations of k and the negabinary representation of -k are all palindromic.at n=38A331895