23844domain: NAppears in sequencesa(n) = Sum{T(i,j)}, 0<=j<=i, 0<=i<=n, T given by A026552.at n=11A026566Number of interior balls in a truncated tetrahedral arrangement.at n=18A092966A digitized pure tuning tone, sampled at standard settings for consumer audio: a(n) = floor(sin(2*Pi*(440/44100)*n)*32767).at n=13A320277