OFFSET
1,2
LINKS
MATHEMATICA
Array[DivisorSigma[1, Apply[Times, FactorInteger[#] /. {p_, e_} /; e > 0 :> Apply[Times, Prime@ Range@ PrimePi@ p]^e]] &, 46] (* Michael De Vlieger, Aug 27 2020 *)
PROG
(PARI)
A034386(n) = prod(i=1, primepi(n), prime(i));
(PARI) A337203(n) = if(1==n, n, my(f=factor(n), h = #f~, prevpid=primepi(f[h, 1]), e=f[h, 2], p, s=1); forstep(i=h-1, 0, -1, if(!i, pid=0, pid=primepi(f[i, 1])); forstep(j=prevpid, (1+pid), -1, p=prime(j); s *= ((p^(1+e)-1)/(p-1))); if(!pid, return(s)); prevpid = pid; e += f[i, 2]); (s));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 22 2020
STATUS
approved