232965domain: NAppears in sequencesa(1) = 1, a(2n) = smallest composite number > (2n-1)-th partial sum of the sequence itself and a(2n+1) = smallest prime > 2n-th partial sum of the sequence.at n=17A076975Position of n! in A025487.at n=24A098718Octagonal numbers (A000567) in which parity of digits alternates.at n=28A297647