171512domain: NAppears in sequencesExpansion of g.f.: exp( Sum_{n>=1} A002203(n)^2 * x^n/n ) where A002203 are the companion Pell numbers.at n=7A204062Number of (w,x,y,z) with all terms in {0,...,n} and (least gapsize)>2.at n=23A212899