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

25, 75, 125, 175, 225, 275, 325, 375, 425, 475, 525, 575, 625, 675, 725, 775, 825, 875, 925, 975, 1025, 1075, 1125, 1175, 1225, 1275, 1325, 1375, 1425, 1475, 1525, 1575, 1625, 1675, 1725, 1775, 1825, 1875, 1925, 1975, 2025, 2075, 2125, 2175, 2225, 2275

Offset

0,1

Comments

Integers that are the product of two integers ending with 5. - Michel Marcus, Mar 16 2019

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

a(n) = 25 + 50*n.

a(n) = a(n-1) + 50. - Harvey P. Dale, Aug 11 2011

From Colin Barker, Jun 27 2012: (Start)

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

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

E.g.f.: 25*(1+2*x)*exp(x). - G. C. Greubel, Sep 06 2019

Example

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

Maple

seq(25*(2*n+1), n=0..50); # G. C. Greubel, Sep 06 2019

Mathematica

Range[25, 2275, 50] (* or *) NestList[#+50&, 25, 50] (* Harvey P. Dale, Aug 11 2011 *)

Prog

(Magma) [25+50*n: n in [0..50]]; // Vincenzo Librandi, Aug 12 2011
(PARI) a(n)=50*n+25 \\ Charles R Greathouse IV, Aug 25 2014
(Sage) [25*(2*n+1) for n in (0..50)] # G. C. Greubel, Sep 06 2019
(GAP) List([0..50], n-> 25*(2*n+1)); # G. C. Greubel, Sep 06 2019

Crossrefs

Cf. A053741, A053743.

Sequence in context: A044544 A045180 A270385 * A123296 A118610 A008852

Adjacent sequences: A053739 A053740 A053741 * A053743 A053744 A053745

Keyword

nonn,easy

Author

Odimar Fabeny, Feb 13 2000

Extensions

More terms from James A. Sellers, Feb 22 2000

Status

approved