28077

Appears in sequences

• Number of stable towers of 2 X 2 LEGO blocks.at n=10A007575
• Antidiagonal sums of square array A082025.at n=36A082190
• Numbers k such that sigma(phi(k)) - phi(sigma(k)) is nonzero and divisible by sigma(k), that is A065395(k)/A000203(k) is a nonzero integer.at n=27A092588
• Number of diamond-free Berge perfect graphs on n nodes.at n=9A123420
• Indices of products of twin primes in the semiprimes.at n=20A131188
• Number of n X n binary arrays symmetric under horizontal reflection with all ones connected only in a 1100-0100-1111 pattern in any orientation.at n=11A146651
• Hash Parker numbers: Integers whose real 32nd root's first six nonzero digits (after the decimal point) rearranged in ascending order are equal to 234477.at n=18A309979
• Total number of parts coprime to n in the partitions of n into 7 parts.at n=42A363325