18158

Appears in sequences

• Least k such that Sum_{i=1..k} 1/phi(i) >= n.at n=18A074467
• Floor( phi * (3/2)^n ) where phi = (1+sqrt(5))/2.at n=23A081226
• Number of words either empty or beginning with the first letter of the cyclic n-ary alphabet, where each letter of the alphabet occurs twice and letters of neighboring word positions are equal or neighbors in the alphabet.at n=15A208880
• Concatenation of n-th prime and n-th nonprime.at n=41A253910
• G.f.: Product_{k>=1} (1 + 2*x^(k^2)) / (1-x^k).at n=27A280224
• a(n) = Sum_{k=1..n} k^2*sigma_2(k), where sigma_2 is A001157.at n=8A364268
• Numbers k such that there exists i >= 1 such that k divides 3^3^i + 1.at n=53A367266