18071

Appears in sequences

• a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(2) = 4.at n=31A050039
• Numerator of 1 + 1/2 + 2/3 + 3/4 + ... + (n-1)/n.at n=9A061483
• Numbers n for which there are exactly eight k such that n = k + reverse(k).at n=37A072432
• Positions where A109890(n) = Sum_{i = 1..n-1} A109890(i).at n=34A111315
• a(n) = 49*n^2 - 78*n + 31.at n=19A157368
• Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^2>=x^2+y^2.at n=33A211803