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A326202
Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = 0 if n > 2 and gcd(n,sigma(n)) = 1, with f(n) = n for all other numbers.
4
1, 2, 3, 3, 3, 4, 3, 3, 3, 5, 3, 6, 3, 7, 8, 3, 3, 9, 3, 10, 3, 11, 3, 12, 3, 13, 3, 14, 3, 15, 3, 3, 16, 17, 3, 3, 3, 18, 3, 19, 3, 20, 3, 21, 22, 23, 3, 24, 3, 3, 25, 26, 3, 27, 3, 28, 3, 29, 3, 30, 3, 31, 3, 3, 3, 32, 3, 33, 34, 35, 3, 36, 3, 37, 3, 38, 3, 39, 3, 40, 3, 41, 3, 42, 3, 43, 44, 45, 3, 46, 47, 48, 3, 49, 50, 51, 3, 3, 52, 3, 3, 53, 3, 54, 55
OFFSET
1,2
COMMENTS
For all i, j:
A305801(i) = A305801(j) => A324401(i) = A324401(j) => a(i) = a(j),
a(i) = a(j) => A009194(i) = A009194(j) => A325964(i) = A325964(j).
LINKS
PROG
(PARI)
up_to = 65537;
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; };
Aux326202(n) = if((n>2) && (1==gcd(n, sigma(n))), 0, n);
v326202 = rgs_transform(vector(up_to, n, Aux326202(n)));
A326202(n) = v326202[n];
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 11 2019
STATUS
approved