18695

Appears in sequences

• Numbers n such that phi(2n-1) = sigma(n).at n=40A067230
• Numbers n such that sigma(n)=phi(n*bigomega(n)-1).at n=34A067877
• Numbers n such that h(n) = 3 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.)at n=16A078420
• Number of partitions of n with rank 3 (the rank of a partition is the largest part minus the number of parts).at n=54A101200
• Expansion of x/(1 -x^2 -x^4 -x^7 -x^8 -x^9 -x^10).at n=33A143351
• Number of partitions p of n such that median(p) >= mean(p).at n=49A240221
• a(n) = number of steps to reach 0 when starting from k = (n^3)-1 and repeatedly applying the map that replaces k with k - A055401(k), where A055401(k) = the number of positive cubes needed to sum to k using the greedy algorithm.at n=53A261228
• Numbers k that are a substring of xPy where k=concatenation(x,y) and xPy is the number of permutations A008279(x,y).at n=40A359012
• The five digits of a(n) and their four successive absolute first differences are all distinct.at n=5A365257