OFFSET
1,3
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65536
FORMULA
a(2n) = a(n).
PROG
(PARI)
allocatemem(2^30);
up_to = 65536;
rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om, invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om, invec[i], i); outvec[i] = u; u++ )); outvec; };
write_to_bfile(start_offset, vec, bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A173557(n) = my(f=factor(n)[, 1]); prod(k=1, #f, f[k]-1); \\ This function from Michel Marcus, Oct 31 2017
write_to_bfile(1, rgs_transform(vector(up_to, n, A173557(n))), "b295877.txt");
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 29 2017
STATUS
approved