%I #9 Nov 15 2024 12:56:13

%S 112375899,871651143,1525038515,3524721824,6058144224,7616307699,

%T 7929320399,9778346864,10799650575,11536526000,13663711775,

%U 20596306224,22326106256,24442111385,26385908912,27394105760,28476579725,31552570400,34148839725,36045427040,40916036304,44037977984,44430326199

%N Numbers k such k | A378056(k) and (k+1) | A378056(k+1).

%o (PARI) is1(k) = {my(d = divisors(k)); !(lcm(apply(x->x+1, d)) % k) && !(lcm(apply(x -> if(x > 1, x-1, x), d)) % k);}

%o lista(kmax) = {my(q1 = is1(1), q2); for(k = 2, kmax, q2 = is1(k); if(q1 && q2, print1(k-1, ", ")); q1 = q2);}

%Y Intersection of A377951 and A377953.

%Y Subsequence of A378058.

%Y Cf. A378055, A378056.

%K nonn

%O 1,1

%A _Amiram Eldar_, Nov 15 2024