Numbers k such that k and k+1 are both products of 2 triangular numbers.

Terms

a(0) =0a(1) =9a(2) =90a(3) =135a(4) =945a(5) =1710a(6) =1890a(7) =4959a(8) =5670a(9) =8910a(10) =10584a(11) =11025a(12) =11934a(13) =13860a(14) =19305a(15) =21735a(16) =26334a(17) =32130a(18) =36855a(19) =44550a(20) =49140a(21) =65340a(22) =107415a(23) =138600a(24) =172080a(25) =239085a(26) =305370a(27) =351540a(28) =366795a(29) =459360