60806

Appears in sequences

• Palindromes that cannot be prefixed and followed by any digit to form a prime.at n=1A032735
• a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes allowed).at n=16A032736
• Composite numbers k such that all the decimal concatenations ik and ikj (i, j = 1...9) are also composite.at n=32A032737
• a(n) cannot be prefixed or followed by any digit to form a prime ('empty' prefixes and suffixes are allowed).at n=10A032738
• Base-10 palindromes that start with 6.at n=30A043041
• Palindromes with exactly 2 palindromic prime factors (counted with multiplicity), and no other prime factors.at n=43A046376
• Palindromes with exactly 2 distinct palindromic prime factors.at n=39A046408
• a(n) = smallest palindrome > a(n-1) such that a(1)*a(2)*...*a(n) + 1 is prime with a(1) = 2.at n=38A051896
• Number of nX3 0..3 arrays with no element less than a strict majority of its horizontal and vertical neighbors.at n=3A231742
• Number of nX4 0..3 arrays with no element less than a strict majority of its horizontal and vertical neighbors.at n=2A231743
• T(n,k)=Number of nXk 0..3 arrays with no element less than a strict majority of its horizontal and vertical neighbors.at n=17A231746
• T(n,k)=Number of nXk 0..3 arrays with no element less than a strict majority of its horizontal and vertical neighbors.at n=18A231746
• Least integer m > 0 with pi(m*n) = sigma(m+n), where pi(.) and sigma(.) are given by A000720 and A000203.at n=21A247604