# Computed 2018-08-12 in GP/PARI CALCULATOR Version 2.9.4 (released) amd64 running linux (x86-64/GMP-6.1.2 kernel) 64-bit version, compiled: Dec 19 2017, gcc version 7.3.0 (Ubuntu 7.3.0-1ubuntu1), threading engine: pthread # with the following program: # # up_to = 16384; # ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om,invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om,invec[i],(1+pt))); outvec; }; # A020639(n) = if(n>1, if(n>n=factor(n, 0)[1, 1], n, factor(n)[1, 1]), 1); \\ From A020639, by Hasler. # v078898 = ordinal_transform(vector(up_to,n,A020639(n))); # A078898(n) = v078898[n]; # memo317833 = Map(); # A317833aux(n) = if(1==n,n,if(mapisdefined(memo317833,n),mapget(memo317833,n),my(v = (A078898(n)-sumdiv(n,d,if((d>1)&&(d