A359564 Primitive terms of A359563: terms of A359563 with no proper divisor in A359563.

63, 273, 513, 585, 825, 2107, 2109, 2255, 3069, 3075, 4329, 4697, 4995, 5425, 5673, 6039, 6643, 6935, 6975, 7105, 7161, 8103, 8349, 8541, 8645, 9855, 10235, 11543, 12625, 13725, 13869, 14497, 14841, 16385, 18639, 18915, 19825, 22165, 25025, 26169, 26533, 30225

Offset

1,1

Comments

Odd numbers that are not in A326835 but all of their proper divisors are in it.

If k is a term then all the odd multiples of k are terms of A359563.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

q[n_] := !UnsameQ @@ EulerPhi[Divisors[n]]; primQ[n_] := q[n] && AllTrue[Divisors[n], # == n || !q[#] &]; Select[Range[1, 30000, 2], primQ]

Prog

(PARI) is1(k) = k>1 && k%2 && numdiv(k) > #Set(apply(x->eulerphi(x), divisors(k)));
is(k) = fordiv(k, d, if(is1(d), return(d==k))); return(0);

Crossrefs

Cf. A326835, A359563, A359565, A359566.

Sequence in context: A326388 A158684 A063398 * A138833 A204736 A160674

Adjacent sequences: A359561 A359562 A359563 * A359565 A359566 A359567

Keyword

nonn

Author

Amiram Eldar, Jan 06 2023

Status

approved