A351082 a(n) = Product_{d|n} A019565(A289814(d)); a product obtained from the 2-digits present in ternary expansions of the divisors of n.

1, 2, 1, 2, 2, 6, 3, 12, 1, 4, 2, 6, 1, 12, 6, 36, 6, 30, 5, 40, 15, 20, 10, 540, 30, 60, 1, 12, 2, 36, 1, 72, 6, 36, 36, 30, 1, 20, 1, 240, 2, 540, 3, 120, 30, 100, 10, 8100, 15, 600, 90, 900, 30, 210, 28, 1008, 35, 28, 14, 7560, 21, 84, 105, 504, 28, 1260, 7, 504, 210, 3024, 42, 94500, 35, 140, 3150, 700, 420, 18900

Offset: 1

Author

Antti Karttunen, Jan 31 2022

Keywords

• nonn
• easy

Crossrefs

Cf. A019565, A289814, A293221, A351081, A351092.

Programs

PARI

A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };
A289814(n) = { my(d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); };
A351082(n) = { my(m=1); fordiv(n,d,m *= A019565(A289814(d))); (m); };

Formula

a(n) = A019565(A289814(n)) * A293222(n).