# Computed 2018-05-18 as follows:
#
# First A064413 data was prepared with Chai Wah Wu's Python-program (dated Dec 08 2014):
#
# from fractions import gcd
#
# A064413_list, l, s, b = [1, 2], 2, 3, {}
#
# outfp = open('b064413_big.txt', 'w')
# outfp.write(str(1) + " " + str(1) + "\n")
# outfp.write(str(2) + " " + str(2) + "\n")
# k = 2
#
# for _ in range(65537):
# i = s
# while True:
# if not i in b and gcd(i, l) > 1:
# A064413_list.append(i)
# k += 1
# outfp.write(str(k) + " " + str(i) + "\n")
# l, b[i] = i, True
# while s in b:
# b.pop(s)
# s += 1
# break
# i += 1
#
# Then a "terms only" text file was prepared with:
# gawk ' { print $2 } ' < b064413_big.txt > b064413_upto65539_terms_only.txt
#
# And then read into GP/PARI CALCULATOR Version 2.9.4 (released) amd64 running mingw (x86-64/GMP-6.1.2 kernel) 64-bit version, compiled: Dec 20 2017, gcc version 4.9.1 (GCC), threading engine: single
#
# v064413 = readvec("b064413_upto65539_terms_only.txt");
# A064413(n) = v064413[n];
# Then its inverse A064664 was prepared:
# m064664 = Map();
# for(n=1,65539,mapput(m064664,A064413(n),n));
# A064664(n) = mapget(m064664,n);
# A304527(n) = -sumdiv(n, d, (d