30246

Appears in sequences

• Composite numbers k such that sigma(k) / d(k) is prime.at n=25A048969
• usigma(n) = 2n + d(n), where d(n) is the number of divisors of n.at n=18A063829
• Number of permutations of length n which avoid the patterns 1432, 2143, 3124; or avoid the patterns 1432, 2314, 3142.at n=9A116793
• Continued fraction expansion for exp( Sum_{n>=1} 1/(n*A086903(n)) ), where A086903(n) = (4+sqrt(15))^n + (4-sqrt(15))^n.at n=9A174502
• Sums of 3 distinct primorials.at n=28A177697
• Number of (n+4)X7 binary arrays with every 1 having exactly three king-move neighbors equal to 1 but with no 2X2 blocks of 1s.at n=7A183460
• T(n,k)=Number of (n+4)X(k+4) binary arrays with every 1 having exactly three king-move neighbors equal to 1 but with no 2X2 blocks of 1s.at n=47A183465
• T(n,k)=Number of (n+4)X(k+4) binary arrays with every 1 having exactly three king-move neighbors equal to 1 but with no 2X2 blocks of 1s.at n=52A183465
• Pairs of Pythagorean numbers differing by 6.at n=41A228875
• Upper Pythagorean twins.at n=20A228877
• Triangle T(n,k) giving the smallest term in "the infinite trunk of factorial beanstalk" (A219666) whose factorial base representation contains n digits (A084558) and the most significant such digit (A099563) is k.at n=26A230428
• Number of (n+2)X(4+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 or 00000011.at n=8A259719
• Differences of the increasing arithmetic progression a^2+a, b^2+b, c^2+c, where b = 5*a+2, c = 7*a+3 and a >= 0.at n=35A260955
• Numbers that are the sum of distinct primorial numbers (A002110) (not including 1).at n=41A290249
• Numbers k such that s(k) = 2*k, where s(k) is the sum of divisors of k that have a square factor (A162296).at n=22A322609
• a(n) = A343046(n, n).at n=32A343047
• Sums of three primorials > 1.at n=42A370137
• Numbers k such that sigma(k) = psi(k) + tau(k).at n=38A387953