30500

Appears in sequences

• Number of up steps in all length n left factors of Dyck paths.at n=14A014314
• Numbers k such that 27*2^k+1 is prime.at n=29A032363
• Numbers k such that k and k^2 use only the digits 0, 2, 3, 5 and 9.at n=45A136891
• a(n) = ceiling(A173510(n)/2).at n=42A173513
• Expansion of g.f. (1-6*x+x^2)/(1-10*x+5*x^2).at n=5A189334
• a(n) is the difference between multiples of 5 with even and odd digit sum in base 4 in interval [0,4^n).at n=9A212500
• Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by three: p(i)<>i and (i-p(i) mod n <= 3 or p(i)-i mod n <= 3).at n=10A260081
• G.f. A(x) satisfies: A(x)^2 = A( x^2/(1-10*x) ), with A(0) = 0.at n=5A264227
• Practical numbers z such that z^2 = x^2 + y^2 for some practical numbers x and y with gcd(x,y,z) = 4.at n=42A294112
• For any k, the cumulative sum a(1) + a(2) + a(3) + ... + a(k) shares at least five digits with a(k). Lexicographically first sequence of positive integers without duplicate terms having this property.at n=28A326640
• Numbers k such that lambda(k) = lambda(k+2), where lambda is the Carmichael lambda function (A002322).at n=33A333742
• Place n equally spaced points around the circumference of a circle and then, for each pair of points, draw two distinct circles, whose radii are the same as the first circle, such that both points lie on their circumferences. The sequence gives the total number of (curved) edges formed.at n=19A371375