18925

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 41.at n=38A020380
• n! has a palindromic prime number of digits.at n=28A035067
• Composite numbers whose prime factors contain no digits other than 5 and 7.at n=27A036320
• Base 3 digits are, in order, the first n terms of the periodic sequence with initial period 2,2,1.at n=8A037560
• Numbers k such that sigma(k^2+1) is a perfect square.at n=16A067465
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, -1), (-1, -1, 0), (0, 0, 1), (0, 1, -1), (1, 0, 0)}.at n=9A149859
• The period after which the powers of n repeat on an 8-digit calculator.at n=19A216068
• a(0)=1; thereafter a(n) = Sum_{k=2..n+1} A006206(k).at n=24A286271
• a(n) = Sum_{1 <= i <= j <= k <= n} gcd(i,j,k).at n=41A344521