25019

Appears in sequences

• Numbers k such that sigma(k+2) = sigma(k).at n=30A007373
• Composite numbers not divisible by 2 or 3 which in base 3 contain their largest proper factor as a substring.at n=22A063132
• Solutions to phi(x + omega(x)) = phi(x) + d(x), where phi() = A000010(), d() = A000005() and omega() = A001221().at n=8A063868
• Numbers k such that A065608(k) = A065608(k+2).at n=15A065064
• Numbers m such that m and m+2 are both brilliant numbers, where brilliant numbers are semiprimes whose prime factors have an equal number of decimal digits, or whose prime factors are equal.at n=14A083284
• Positions of records in the continued fraction expansion A100864.at n=16A100866
• Indices of primes in the sequence defined by A(0) = 23, A(n) = 10*A(n-1) + 63 for n > 0.at n=14A101973
• Number of partitions of n in which each part, with the possible exception of the largest, occurs at least twice.at n=50A116931
• Numbers k such that k and k+2 have the same number (A000005) and sum of divisors (A000203).at n=12A229254
• Numbers k such that (29*10^k + 19)/3 is prime.at n=23A280925
• Number of anti-transitive rooted trees with n nodes.at n=13A306844
• Numbers k such that the sum of the numbers from 1 to k and that from 1 to k+1 share the same sum of divisors.at n=18A375819
• Numbers k such that s(k) = s(k+2), where s(k) is the sum of odd divisors of k (A000593).at n=10A387920