G.f.: (1+38*x+263*x^2+484*x^3+263*x^4+38*x^5+x^6)/(1-x)^7.

Terms

a(0) =1a(1) =45a(2) =557a(3) =3473a(4) =14417a(5) =45965a(6) =121997a(7) =283137a(8) =593281a(9) =1147213a(10) =2079309a(11) =3573329a(12) =5873297a(13) =9295469a(14) =14241389a(15) =21212033a(16) =30823041a(17) =43821037a(18) =61101037a(19) =83724945a(20) =112941137a(21) =150205133a(22) =197201357a(23) =255865985a(24) =328410881a(25) =417348621a(26) =525518605