485751domain: NAppears in sequencesExpansion of 1/((1-2x)(1-3x)(1-5x)(1-11x)).at n=5A025935Partition the terms of the harmonic series into groups sequentially so that the sum of each group is equal to or minimally greater than 1; then a(n) is the number of terms in the n-th group.at n=13A331028