18381

Appears in sequences

• Numbers k such that 7*2^k - 1 is prime.at n=8A001771
• Lucky numbers that are both palindromic and nonprime.at n=34A031880
• Palindromic Super-2 Numbers.at n=32A032750
• Numbers that are palindromic, divisible by 11 and have an odd number of digits.at n=15A045571
• Largest palindromic substring in 6^n.at n=34A046264
• Largest palindromic substring in 7^n.at n=43A046265
• Composite palindromes whose sum of prime factors is prime (counted with multiplicity).at n=42A046365
• Palindromic odd composite numbers that are the products of an odd number of distinct primes.at n=37A075808
• Palindromes n such that 10n01 is a prime.at n=30A099744
• Consider all (2n+1)-digit palindromic primes of the form 10...0M0...01 (so that M is a palindrome with <= 2n-1 digits); a(n) = smallest such M.at n=30A100026
• Numbers k such that k and k^2 use only the digits 1, 3, 6, 7 and 8.at n=10A137038
• Palindromic Ulam numbers.at n=32A173542
• Happy palindromic numbers.at n=40A216237
• Number of nonnegative solutions to x^3 + y^3 + z^3 <= n^3.at n=29A224215
• Numbers n such that n^10+10 is prime.at n=29A239347
• a(n) = number of triangles with integer sides i <= j <= k with radius of circumcircle <= n.at n=31A331229