A340364 a(n) = gcd(A005940(n), A324106(n)), where A324106(n) is multiplicative with a(p^e) = A005940(p^e).

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

Antti Karttunen, Table of n, a(n) for n = 1..16384

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

Cf. A005940, A324106, A340362, A340365, A340366.

Cf. also A339969.

Sequence in context: A269865 A269387 A207801 * A324106 A252753 A357268

Adjacent sequences: A340361 A340362 A340363 * A340365 A340366 A340367

Keyword

nonn

Author

Antti Karttunen, Jan 06 2021

Status

approved