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A236563 a(p^n)=p^(n+1)(p-1) if p is prime and a(nm)=lcm(a(n),a(m)) if gcd(n,m)=1.

%I A236563 #23 Feb 27 2014 08:35:41
%S A236563 1,4,18,8,100,36,294,16,54,100,1210,72,2028,588,900,32,4624,108,6498,
%T A236563 200,882,2420,11638,144,500,2028,162,1176,23548,900,28830,64,10890,
%U A236563 4624,14700,216,49284,12996,6084,400,67240,1764,77658,4840,2700,23276,101614
%N A236563 a(p^n)=p^(n+1)(p-1) if p is prime and a(nm)=lcm(a(n),a(m)) if gcd(n,m)=1.
%H A236563 Vincenzo Librandi, <a href="/A236563/b236563.txt">Table of n, a(n) for n = 1..1000</a>
%t A236563 fa=FactorInteger; lam[p_, s_] := p^(s + 1)(p - 1); lam[1] = 1; lam[n_] := {aux = 1; Do[aux = LCM[aux, lam[fa[n][[i,1]], fa[n][[i, 2]]]], {i, 1, Length[fa[n]]}]; aux}[[1]];Array[lam,100]
%o A236563 (Haskell)
%o A236563 a236563 n = foldl lcm 1 $ zipWith (\p e -> p ^ (e + 1) * (p - 1))
%o A236563                                   (a027748_row n) (a124010_row n)
%o A236563 -- _Reinhard Zumkeller_, Feb 27 2014
%Y A236563 Cf. A027748, A124010.
%K A236563 nonn
%O A236563 1,2
%A A236563 _José María Grau Ribas_, Feb 22 2014