OFFSET
1,1
COMMENTS
Numbers k such that k and k+1 are both in A359565.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
q[n_] := q[n] = Max[Tally[EulerPhi[Divisors[n]]][[;; , 2]]] > 2; Select[Range[3*10^6], q[#] && q[# + 1] &]
PROG
(PARI) is(k) = vecmax(matreduce(apply(x->eulerphi(x), divisors(k)))[, 2]) > 2;
lista(kmax) = {my(q1 = 0, q2); for(k = 2, kmax, q2 = is(k); if(q1 && q2, print1(k-1, ", ")); q1 = q2); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Jun 08 2024
STATUS
approved