42251

Appears in sequences

• Generalized Stirling numbers, [n+2,n]_2.at n=22A001701
• Numbers k such that k and k+1 have the same sum of squarefree divisors, or sqf(k) = sqf(k+1), where sqf(k) = A048250(k).at n=14A063964
• Numbers k such that sigma(triangular(k)) = sigma(k)^2.at n=10A232355
• Numbers k with the property that it is possible to write the base 2 expansion of k as concat(a_2,b_2), with a_2>0 and b_2>0 such that, converting a_2 and b_2 to base 10 as a and b, we have sigma(a + b) = sigma(k).at n=18A258843
• Numbers k such that k and k + 1 have the same norm of the sum of unitary divisors in Gaussian integers (A332474).at n=6A332475
• Numbers k such that abs(A328258(k)) = abs(A328258(k+1)).at n=32A348586
• Number k such that A033634(k) = A033634(k+1).at n=16A349224
• Number of integer partitions of n of length > 2 whose second differences have median 0.at n=42A360682