cp's OEIS Frontend

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.

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

Original entry on oeis.org

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

Views

Author

Odimar Fabeny, Feb 13 2000

Keywords

Comments

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

Examples

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

Crossrefs

Programs

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

Extensions

More terms from James Sellers, Feb 22 2000