A355002 Numbers k that share a prime factor with A355456(k).

135, 140, 285, 435, 455, 675, 700, 855, 885, 910, 945, 980, 1120, 1185, 1305, 1335, 1365, 1425, 1435, 1485, 1540, 1635, 1755, 1820, 1995, 2085, 2175, 2235, 2275, 2295, 2380, 2565, 2574, 2655, 2660, 2685, 2870, 2905, 2985, 3045, 3105, 3135, 3185, 3220, 3311, 3375, 3395, 3435, 3500, 3555, 3585, 3640, 3705, 3915, 4005

Offset

1,1

Comments

Numbers k such that A324198(k) and A342671(k) are not relatively prime.

Links

Table of n, a(n) for n=1..55.

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to primorial base

Index entries for sequences related to sigma(n)

Prog

(PARI)
A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A355442(n) = gcd(A003961(n), A276086(n));
A355456(n) = gcd(sigma(n), A355442(n));
isA355002(n) = (1!=gcd(n, A355456(n)));

Crossrefs

Cf. A000203, A003961, A276086, A324644, A342671, A351459, A355442, A355456.

Subsequence of A324584 and of A349166.

Sequence in context: A348815 A230699 A335950 * A038369 A066282 A235809

Adjacent sequences: A354999 A355000 A355001 * A355003 A355004 A355005

Keyword

nonn

Author

Antti Karttunen, Jul 13 2022

Status

approved