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 A133051 #7 Oct 03 2017 20:52:09 %S A133051 36,784,246016,66064384,1125625045712896,73785850399226331136, %T A133051 18889393873953262403584,5316911978187903335626628646131728384, %U A133051 7067388259113537312203207839508118631205775474686154970915275376716414976 %N A133051 Squares of perfect numbers. %F A133051 a(n) = A000396(n)^2 %e A133051 a(2)=784 because the second perfect number is 28 and 28^2=784. %t A133051 Select[Range[9000], DivisorSigma[1,#]== 2*# &]^2 (* _G. C. Greubel_, Oct 03 2017 *) %Y A133051 Cf. A000290, A001248. Perfect numbers: A000396. %K A133051 nonn %O A133051 1,1 %A A133051 _Omar E. Pol_, Oct 30 2007 %E A133051 More terms from _Olaf Voß_, Feb 13 2008