login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A342903 a(n) is the smallest number that is the sum of n positive squares in two ways. 10
50, 27, 28, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

This is r(n,2,2) in Alter's notation.

LINKS

Table of n, a(n) for n=2..71.

R. Alter, Computations and generalizations on a remark of Ramanujan, pp. 182-196 of "Analytic Number Theory (Philadelphia, 1980)", ed. M. I. Knopp, Lect. Notes Math., Vol. 899, 1981. See Eq. (15), page 188.

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

FORMULA

a(n) = n+15 for n >= 5.

EXAMPLE

a(2) = 50 = 1+49 = 25+25.

a(3) = 27 = 1+1+25 = 9+9+9.

a(5) = 20 = 1+1+1+1+16 = 4+4+4+4+4.

CROSSREFS

Cf. A230563, A342902.

Sequence in context: A033370 A090691 A033980 * A207149 A207142 A244277

Adjacent sequences: A342900 A342901 A342902 * A342904 A342905 A342906

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Apr 03 2021

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 4 05:49 EST 2023. Contains 360046 sequences. (Running on oeis4.)