This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A377953 #12 Nov 16 2024 04:29:24
%S A377953 310155,2566025,2853135,5746455,6515145,7329608,8459360,11291091,
%T A377953 15446079,16181535,26782224,26942475,32364464,34318844,36951200,
%U A377953 38579442,38596239,38763900,40564524,41273154,47308976,47648600,49309715,50163735,51177224,52573520,58524465,63668079
%N A377953 Numbers k such that k | A084190(k) and (k+1) | A084190(k+1).
%C A377953 Numbers k such that k and k+1 are both terms in A377952.
%H A377953 Amiram Eldar, <a href="/A377953/b377953.txt">Table of n, a(n) for n = 1..1500</a>
%t A377953 q[n_] := q[n] = n == 1 || Divisible[LCM @@ (Rest @ Divisors[n] - 1), n] ; Select[Range[3*10^6], q[#] && q[# + 1] &]
%o A377953 (PARI) is1(k) = !(lcm(apply(x -> if(x > 1, x-1, x), divisors(k))) % k);
%o A377953 lista(kmax) = {my(q1 = is1(1), q2); for(k = 2, kmax, q2 = is1(k); if(q1 && q2, print1(k-1, ", ")); q1 = q2);}
%Y A377953 Cf. A084190.
%Y A377953 Subsequence of A377952.
%Y A377953 Similar sequences: A355332, A377949, A377951.
%K A377953 nonn
%O A377953 1,1
%A A377953 _Amiram Eldar_, Nov 12 2024