login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A169618 Table with T(n,k) = the number of ways to represent k as the sum of a square and a cube modulo n. 1
1, 2, 2, 3, 3, 3, 6, 6, 2, 2, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 11, 8, 12, 2, 6, 3, 12, 20, 4, 4, 12, 4, 4, 4, 15, 15, 6, 6, 6, 6, 6, 6, 15, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 18, 18, 6, 6, 18, 18, 6, 6, 18, 18, 6, 6, 13, 11, 18, 8, 20, 15, 6 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The top left corner is T(1,0).

It appears that this table does not contain any 0's.

It appears that row n is constant iff n is squarefree, and no prime divisor of n is == 1 (mod 6). It is not hard to show that such rows are constant, since the cubes are equi-distributed in such moduli.

LINKS

Table of n, a(n) for n=1..85.

EXAMPLE

The 6 ways to represent 0 (mod 4) are 0^2+0^3, 0^2+2^3, 1^2+3^3, 2^2+0^3, 2^2+2^3, and 3^2+3^3.

PROG

(PARI) al(n)=local(v); v=vector(n); for(i=0, n-1, for(j=0, n-1, v[(i^2+j^3)%n+1]++)); v

CROSSREFS

Cf. A022549, A002476, A045309.

Sequence in context: A239518 A293924 A307730 * A175454 A157501 A080968

Adjacent sequences:  A169615 A169616 A169617 * A169619 A169620 A169621

KEYWORD

nonn,tabl

AUTHOR

Franklin T. Adams-Watters, Dec 03 2009

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 22 21:18 EDT 2019. Contains 325226 sequences. (Running on oeis4.)