a(n) = round(n*Pi^n).

Terms

a(0) =3a(1) =20a(2) =93a(3) =390a(4) =1530a(5) =5768a(6) =21142a(7) =75908a(8) =268282a(9) =936480a(10) =3236244a(11) =11091230a(12) =37747805a(13) =127710397a(14) =429872190a(15) =1440515533a(16) =4808357581a(17) =15994483255a(18) =53039715042a(19) =175399135922a(20) =578584268700