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 A053742 Sum of odd numbers in range 10*n to 10*n+9. 7

%I

%S 25,75,125,175,225,275,325,375,425,475,525,575,625,675,725,775,825,

%T 875,925,975,1025,1075,1125,1175,1225,1275,1325,1375,1425,1475,1525,

%U 1575,1625,1675,1725,1775,1825,1875,1925,1975,2025,2075,2125,2175,2225,2275

%N Sum of odd numbers in range 10*n to 10*n+9.

%C Integers that are the product of two integers ending with 5. - _Michel Marcus_, Mar 16 2019

%H Vincenzo Librandi, <a href="/A053742/b053742.txt">Table of n, a(n) for n = 0..10000</a>

%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).

%F a(n) = 25 + 50*n.

%F a(n) = a(n-1) + 50. - _Harvey P. Dale_, Aug 11 2011

%F From _Colin Barker_, Jun 27 2012: (Start)

%F a(n) = 2*a(n-1) - a(n-2).

%F G.f.: 25*(1+x)/(1-x)^2. (End)

%F E.g.f.: 25*(1+2*x)*exp(x). - _G. C. Greubel_, Sep 06 2019

%e 25 = 1+3+5+7+9; 75 = 11+13+15+17+19; ...

%p seq(25*(2*n+1), n=0..50); # _G. C. Greubel_, Sep 06 2019

%t Range[25,2275,50] (* or *) NestList[#+50&,25,50] (* _Harvey P. Dale_, Aug 11 2011 *)

%o (MAGMA) [25+50*n: n in [0..50]]; // _Vincenzo Librandi_, Aug 12 2011

%o (PARI) a(n)=50*n+25 \\ _Charles R Greathouse IV_, Aug 25 2014

%o (Sage) [25*(2*n+1) for n in (0..50)] # _G. C. Greubel_, Sep 06 2019

%o (GAP) List([0..50], n-> 25*(2*n+1)); # _G. C. Greubel_, Sep 06 2019

%Y Cf. A053741, A053743.

%K nonn,easy

%O 0,1

%A _Odimar Fabeny_, Feb 13 2000

%E More terms from _James A. Sellers_, Feb 22 2000

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Last modified November 13 17:34 EST 2019. Contains 329106 sequences. (Running on oeis4.)