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A340364
a(n) = gcd(A005940(n), A324106(n)), where A324106(n) is multiplicative with a(p^e) = A005940(p^e).
4
1, 2, 3, 4, 5, 6, 9, 8, 7, 10, 15, 12, 25, 18, 3, 16, 11, 14, 21, 20, 1, 30, 45, 24, 49, 50, 75, 36, 125, 6, 81, 32, 1, 22, 3, 28, 55, 42, 3, 40, 77, 2, 105, 60, 35, 90, 135, 48, 121, 98, 3, 100, 245, 150, 75, 72, 7, 250, 375, 12, 625, 162, 9, 64, 1, 2, 39, 44, 5, 6, 99, 56, 91, 110, 3, 84, 5, 6, 189, 80, 143, 154, 231
OFFSET
1,2
LINKS
FORMULA
a(n) = gcd(A005940(n), A324106(n)) = gcd(A005940(n), A340362(n)).
PROG
(PARI)
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ From A005940
A324106(n) = { my(f=factor(n)); prod(i=1, #f~, A005940(f[i, 1]^f[i, 2])); };
A340364(n) = gcd(A005940(n), A324106(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 06 2021
STATUS
approved