Number of strings of numbers x(i=1..n) in 0..7 with sum i*x(i) equal to n*7.

Terms

a(0) =1a(1) =4a(2) =22a(3) =107a(4) =471a(5) =1842a(6) =6575a(7) =21713a(8) =67105a(9) =195760a(10) =543050a(11) =1440869a(12) =3674381a(13) =9042422a(14) =21548644a(15) =49872800a(16) =112387351a(17) =247136196a(18) =531320447a(19) =1118701390a(20) =2310261518a(21) =4685733808a(22) =9345070552a(23) =18346037917a(24) =35487652677a(25) =67696833402