a(n) = 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6.

Terms

a(0) =1a(1) =28a(2) =769a(3) =7108a(4) =36409a(5) =131836a(6) =380713a(7) =937924a(8) =2054353a(9) =4110364a(10) =7654321a(11) =13446148a(12) =22505929a(13) =36167548a(14) =56137369a(15) =84557956a(16) =124076833a(17) =177920284a(18) =249972193a(19) =344857924a(20) =468033241a(21) =625878268a(22) =825796489a(23) =1076318788