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 A083081 #12 Mar 28 2024 21:54:30 %S A083081 1,13,229,4921,128841,4022341,146450893,6103787761,286833509137, %T A083081 15011892880381,866190689012661,54637591044108073,3740820141248285785, %U A083081 276304073198956644661,21900911192388373534621 %N A083081 First superdiagonal of number array A083075. %H A083081 Vincenzo Librandi, <a href="/A083081/b083081.txt">Table of n, a(n) for n = 1..300</a> %F A083081 a(n) = ((n-1)*(2n+1)^n + 1)/n. %o A083081 (Magma) [((n-1)*(2*n+1)^n+1)/n: n in [1..20]]; // _Vincenzo Librandi_, Nov 12 2011 %Y A083081 Cf. A083080, A083082. %K A083081 easy,nonn %O A083081 1,2 %A A083081 _Paul Barry_, Apr 23 2003