30012

Appears in sequences

• Number of ordered 5-tuples of integers from [ 2,n ] with no common factors among quadruples.at n=19A015655
• k sequence associated with A112550.at n=4A112551
• 2n^4+6n^2+4 = 2(n^2+1)(n^2+2).at n=10A120571
• Records in A185439; record gaps between consecutive emirps.at n=9A185441
• E.g.f.: exp( Sum_{n>=1} (1 - exp(-n*x))^n / n ).at n=5A244437
• Numbers n such that n is both the average of some twin prime pair p, q (q = p+2) (i.e., n = p+1 = q-1) and is also the arithmetic mean of the four numbers consisting of the two primes before p and the two primes after q.at n=36A256620
• Least common multiple of 7*n+1 and 7*n-1.at n=35A282286
• Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=16A302636
• Number of partitions of n with at most four part sizes.at n=47A364793
• a(n) = A276085(n) - A003415(n), where A003415 is the arithmetic derivative and A276085 is the primorial base log-function.at n=33A373146
• a(n) = A276085(n) - A003415(n), where A003415 is the arithmetic derivative and A276085 is the primorial base log-function.at n=50A373146
• Length of the long leg in the unique primitive Pythagorean triple (x,y,z) such that (x-y+z)/2 is A000032(n) and such that its long leg and its hypotenuse are consecutive natural numbers.at n=10A382379