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!)
A101311 Decimal numbers n such that after possibly prefixing a leading 0 to n, the resulting number n' can be broken into 2 strings of the same length, n' = xy, such that x^2+y^2 = n. 7
1, 1233, 8833, 10100, 990100, 5882353, 94122353, 1765038125, 2584043776, 7416043776, 8235038125, 116788321168, 123288328768, 876712328768, 883212321168, 7681802663025, 8896802846976, 13793103448276 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Define a map s_2(n) as follows. If n has an even number of digits, say n = abcdef, the map is n -> s_2(n) := (ab)^2+(cd)^2+(ef)^2. If n has an odd number of digits, say n = abcde, the map is n -> s_2(n) = a^2+(bc)^2+(de)^2. The sequence {s_2(n), n >= 0} does not have its own entry in the OEIS because it begins {0, 1, ..., 9801, 1, 2, 5, ...} and agrees with A000290 for the first 100 terms. There are exactly three numbers such that s_2(n) = n, namely 1, 1233, 8833. - N. J. A. Sloane and Pieter Post, May 11 2015
LINKS
EXAMPLE
1233 is in the sequence because 12^2+33^2 = 1233.
5882353 is in the sequence because 588^2+2353^2 = 5882353.
CROSSREFS
See A064942 for another version.
Sequence in context: A270540 A206272 A064942 * A055616 A104971 A193492
KEYWORD
nonn,base
AUTHOR
Colin Barker, Jul 31 2007, Aug 01 2007
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 July 18 06:32 EDT 2024. Contains 374377 sequences. (Running on oeis4.)