a(n) = 7^n - 6*6^n + 15*5^n - 20*4^n + 15*3^n - 6*2^n + 1.
A228909
a(n) = 7^n - 6*6^n + 15*5^n - 20*4^n + 15*3^n - 6*2^n + 1.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =720a(7) =20160a(8) =332640a(9) =4233600a(10) =46070640a(11) =451725120a(12) =4115105280a(13) =35517081600a(14) =294293759760
External references
- oeis: A228909