20140
domain: N
Appears in sequences
- a(n) is the concatenation of n and 7n.at n=19A009441
- a(n) = 1 + ((6*n-1)*2^n + (-1)^n)/3.at n=10A174836
- G.f.: (t^5 + 2*t^4 + t^3 + 2*t^2 + t) / (t^6 + t^5 - 2*t^4 - 5*t^3 - 2*t^2 + t + 1).at n=18A180510
- Number of compositions of n with exactly 7 transitions between different parts.at n=6A244719
- Ulam numbers u such that 5*u is also an Ulam number.at n=33A287613
- Sum of the squares of the parts in the partitions of n into two distinct parts.at n=39A294286