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 A053742 #34 Jul 02 2025 16:01:59 %S A053742 25,75,125,175,225,275,325,375,425,475,525,575,625,675,725,775,825, %T A053742 875,925,975,1025,1075,1125,1175,1225,1275,1325,1375,1425,1475,1525, %U A053742 1575,1625,1675,1725,1775,1825,1875,1925,1975,2025,2075,2125,2175,2225,2275 %N A053742 Sum of odd numbers in range 10*n to 10*n+9. %C A053742 Integers that are the product of two integers ending with 5. - _Michel Marcus_, Mar 16 2019 %H A053742 Vincenzo Librandi, <a href="/A053742/b053742.txt">Table of n, a(n) for n = 0..10000</a> %H A053742 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A053742 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1). %F A053742 a(n) = 25 + 50*n. %F A053742 a(n) = a(n-1) + 50. - _Harvey P. Dale_, Aug 11 2011 %F A053742 From _Colin Barker_, Jun 27 2012: (Start) %F A053742 a(n) = 2*a(n-1) - a(n-2). %F A053742 G.f.: 25*(1+x)/(1-x)^2. (End) %F A053742 E.g.f.: 25*(1+2*x)*exp(x). - _G. C. Greubel_, Sep 06 2019 %e A053742 25 = 1+3+5+7+9; 75 = 11+13+15+17+19; ... %p A053742 seq(25*(2*n+1), n=0..50); # _G. C. Greubel_, Sep 06 2019 %t A053742 Range[25,2275,50] (* or *) NestList[#+50&,25,50] (* _Harvey P. Dale_, Aug 11 2011 *) %o A053742 (Magma) [25+50*n: n in [0..50]]; // _Vincenzo Librandi_, Aug 12 2011 %o A053742 (PARI) a(n)=50*n+25 \\ _Charles R Greathouse IV_, Aug 25 2014 %o A053742 (Sage) [25*(2*n+1) for n in (0..50)] # _G. C. Greubel_, Sep 06 2019 %o A053742 (GAP) List([0..50], n-> 25*(2*n+1)); # _G. C. Greubel_, Sep 06 2019 %Y A053742 Cf. A053741, A053743. %K A053742 nonn,easy %O A053742 0,1 %A A053742 _Odimar Fabeny_, Feb 13 2000 %E A053742 More terms from _James Sellers_, Feb 22 2000