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 A053743 #20 Jul 02 2025 16:01:59 %S A053743 45,145,245,345,445,545,645,745,845,945,1045,1145,1245,1345,1445,1545, %T A053743 1645,1745,1845,1945,2045,2145,2245,2345,2445,2545,2645,2745,2845, %U A053743 2945,3045,3145,3245,3345,3445,3545,3645,3745,3845,3945,4045,4145,4245,4345 %N A053743 Sum of numbers in range 10*n to 10*n+9. %H A053743 Harvey P. Dale, <a href="/A053743/b053743.txt">Table of n, a(n) for n = 0..1000</a> %H A053743 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A053743 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A053743 a(n) = 100*n + 45. %F A053743 From _Colin Barker_, Jun 26 2012: (Start) %F A053743 a(n) = 2*a(n-1) - a(n-2). %F A053743 G.f.: 5*(9+11*x)/(1-x)^2. (End) %F A053743 E.g.f.: 5*(9 + 20*x)*exp(x). - _G. C. Greubel_, Sep 06 2019 %e A053743 45 = sum of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9; %e A053743 145 = sum of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19. %p A053743 seq(5*(20*n+9), n=0..50); # _G. C. Greubel_, Sep 06 2019 %t A053743 LinearRecurrence[{2,-1},{45,145},50] (* or *) 100*Range[50]-55 (* _Harvey P. Dale_, Feb 03 2019 *) %o A053743 (PARI) vector(50, n, 5*(20*n -11)) \\ _G. C. Greubel_, Sep 06 2019 %o A053743 (Magma) [5*(20*n+9): n in [0..50]]; // _G. C. Greubel_, Sep 06 2019 %o A053743 (Sage) [5*(20*n+9) for n in (0..50)] # _G. C. Greubel_, Sep 06 2019 %o A053743 (GAP) List([0..50], n-> 5*(20*n+9)); # _G. C. Greubel_, Sep 06 2019 %Y A053743 Cf. A053741, A053742. %K A053743 nonn,easy %O A053743 0,1 %A A053743 _Odimar Fabeny_, Feb 13 2000 %E A053743 More terms from _James Sellers_, Feb 22 2000