Number of (w,x,y,z) with all terms in {0,...,n} and (least gapsize)=2.

Terms

a(0) =0a(1) =0a(2) =2a(3) =14a(4) =58a(5) =168a(6) =376a(7) =716a(8) =1224a(9) =1936a(10) =2888a(11) =4116a(12) =5656a(13) =7544a(14) =9816a(15) =12508a(16) =15656a(17) =19296a(18) =23464a(19) =28196a(20) =33528a(21) =39496a(22) =46136a(23) =53484a(24) =61576a(25) =70448a(26) =80136a(27) =90676a(28) =102104a(29) =114456