A366795 a(n) = A344695(A005940(1+n)), where A344695(n) = gcd(psi(n), sigma(n)), and A005940 is the Doudna sequence.

1, 3, 4, 1, 6, 12, 1, 3, 8, 18, 24, 4, 1, 3, 4, 1, 12, 24, 32, 6, 48, 72, 6, 12, 1, 3, 4, 1, 6, 12, 1, 3, 14, 36, 48, 8, 72, 96, 8, 18, 96, 144, 192, 24, 8, 18, 24, 4, 1, 3, 4, 1, 6, 12, 1, 3, 8, 18, 24, 8, 1, 3, 4, 1, 18, 42, 56, 12, 84, 144, 12, 24, 112, 216, 288, 32, 12, 24, 32, 6, 168, 288, 384, 48, 576, 576

Offset

0,2

Links

Antti Karttunen, Table of n, a(n) for n = 0..16384

Prog

(PARI)
A001615(n) = if(1==n, n, my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1))); \\ After code in A001615
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
A344695(n) = gcd(sigma(n), A001615(n));
A366795(n) = A344695(A005940(1+n));

Crossrefs

Cf. A005940, A344695, A366796 (rgs-transform).

Cf. also A346471, A366801, A366803.

Sequence in context: A193794 A378217 A281862 * A092261 A380087 A367991

Adjacent sequences: A366792 A366793 A366794 * A366796 A366797 A366798

Keyword

nonn

Author

Antti Karttunen, Oct 26 2023

Status

approved