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 A122483 #18 Sep 19 2022 06:19:03 %S A122483 6,140,312,1560,14384,18018,40992,2337400,7012200,11027016,231402600, %T A122483 534775296,9866296440,11453072202 %N A122483 Numbers m such that A049060(m)*sigma(m) = k*uphi(m)*m for some integer k. %C A122483 If both 2^n-3 and 2^n-1 are prime then numbers of the form 2^(n-1)*(M_n-2)*M_n appear in the sequence, where M_n means Mersenne prime. %e A122483 2^8*7*19*37*73*509, 2^8*5*7*19*37*509, 2^8*5^2*7*19*29*31*37*509, 2^9*3*11*31*1021, 2^9*3*7*11^2*19*31*131*1021, 2^11*3^6*5*7*13*23*137*467*1093*4093, 2^13*3*11*43*127*16381, 2^13*3*7*11^2*19*43*127*131*16381 are terms, but there may be many other terms between 3*10^7 and them. %t A122483 f[p_, e_] := (p^(e+1)-2*p+1) * (p^(e+1)-1)/((p-1)^2 * (p^e - 1)); q[n_] := IntegerQ[(Times @@ f @@@ FactorInteger[n])/n]; Select[Range[2, 10^5], q] (* _Amiram Eldar_, Sep 19 2022 *) %Y A122483 Cf. A123124, A000203 (sigma), A047994 (uphi), A049060. %K A122483 nonn,more %O A122483 1,1 %A A122483 _Yasutoshi Kohmoto_, Sep 30 2006 %E A122483 More terms from _R. J. Mathar_, Oct 01 2006 %E A122483 a(12)-a(14) from _Amiram Eldar_, Sep 19 2022