A187123 - OEIS

%I #8 Oct 15 2024 18:51:56

%S 1,4,22,164,1599,19624,292799,5162063,105139954,2430528374,

%T 62877375426,1799698534522,56461862815496,1926534563625822,

%U 71024188655886038,2813193432059656268,119136308527407025379,5371507426340905440926

%N Row sums of triangle A187120.

%C Definition of triangle: A187120(n,k) = [y^k] R_{n-1}(y+y^2) for k=3..n, n>3, where R_n(y) is the n-th row polynomial starting with R_3(y)=y^3.

%o (PARI) {a(n)=local(Rn=y^3);for(m=3,n-1,Rn=subst(truncate(Rn),y,y+y^2+O(y^m)));subst(truncate(Rn),y,1)}

%Y Cf. A187120, A135083, A187121, A187122, A187124.

%K nonn

%O 3,2

%A _Paul D. Hanna_, Mar 08 2011