1-sequence of reduction of hexagonal numbers sequence by x^2 -> x+1.

Terms

a(0) =0a(1) =6a(2) =21a(3) =77a(4) =212a(5) =542a(6) =1270a(7) =2830a(8) =6043a(9) =12503a(10) =25208a(11) =49772a(12) =96572a(13) =184646a(14) =348641a(15) =651201a(16) =1204908a(17) =2211018a(18) =4027570a(19) =7288750a(20) =13113415a(21) =23468331a(22) =41799216a(23) =74124312a(24) =130925112a(25) =230408262a(26) =404121645a(27) =706605365a(28) =1231946948a(29) =2142132278