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 A109766 #12 Aug 05 2023 04:12:37 %S A109766 12,40,70,88,1888,4030,5830,8925,32128,32445,78975,442365,521728, %T A109766 1848964,8378368,34359083008,66072609790 %N A109766 Admirable numbers such that the subtracted divisor is prime. %C A109766 549753192448 is also a term. - _Donovan Johnson_, Sep 08 2012 %e A109766 a(2) = 40 because 1+2+4+8+10+20-5 = 40 and the subtracted divisor is prime. %t A109766 q[n_] := (ab = DivisorSigma[1, n] - 2 n) > 0 && EvenQ[ab] && ab/2 < n && Divisible[n, ab/2] && PrimeQ[ab/2]; Select[Range[2*10^6], q] (* _Amiram Eldar_, Aug 05 2023 *) %Y A109766 Cf. A111592. %K A109766 nonn,more %O A109766 1,1 %A A109766 _Jason Earls_, Aug 13 2005 %E A109766 a(15) from _Donovan Johnson_, Sep 27 2008 %E A109766 a(16)-a(17) from _Donovan Johnson_, Sep 08 2012