First differences of A075681.

Terms

a(0) =0a(1) =2a(2) =19a(3) =39a(4) =61a(5) =86a(6) =114a(7) =145a(8) =179a(9) =216a(10) =256a(11) =299a(12) =345a(13) =394a(14) =446a(15) =501a(16) =559a(17) =620a(18) =684a(19) =751a(20) =821a(21) =894a(22) =970a(23) =1049a(24) =1131a(25) =1216a(26) =1304a(27) =1395a(28) =1489a(29) =1586