|
Search: id:A138853
|
|
|
| A138853 |
|
Numbers which are the sum of 3 cubes of distinct odd primes. |
|
+0
4
|
|
| 495, 1483, 1701, 1799, 2349, 2567, 2665, 3555, 3653, 3871, 5065, 5283, 5381, 6271, 6369, 6587, 7011, 7137, 7229, 7235, 7327, 7453, 8217, 8315, 8441, 8533, 9083, 9181, 9399, 10387, 11799, 11897, 12115, 12319, 12537, 12635, 13103, 13525, 13623, 13841
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Dropping the restriction to odd primes would add to this sequence of odd terms the sequence of even terms of the form 8+p(i)^3+p(j)^3 (i>j>1), i.e. 8+{ even terms of A120398 }, cf. A138854.
Values up to 8315 confirmed by R. J. Mathar.
|
|
LINKS
|
Index to sequences related to sums of cubes.
|
|
FORMULA
|
A138853={ p(i)^3+p(j)^3+p(k)^3 ; i>j>k>1 }
|
|
PROGRAM
|
(PARI) isA138853(n)={ local( c, d); n>494 & forprime( p=floor( sqrtn( n\3+1, 3))+1, floor( sqrtn( n-151, 3)), d=n-p^3; forprime( q=floor( sqrtn( d\2+1, 3))+1, min( p-1, floor( sqrtn( d-26, 3))), round( sqrtn( c=d-q^3, 3 ))^3==c | next; isprime( round( sqrtn( c, 3 ))) & return(1)))}
forstep(n=3^3+5^3+7^3, 10^5, 2, isA138853(n)&print1(n", "))
|
|
CROSSREFS
|
Cf. A024975 (a^3+b^3+c^3, a>b>c>0), A122723 (primes in A024975), A138854, A120398.
Sequence in context: A059828 A160851 A031898 this_sequence A164716 A164718 A151965
Adjacent sequences: A138850 A138851 A138852 this_sequence A138854 A138855 A138856
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Maximilian F. Hasler (www.univ-ag.fr/~mhasler), Apr 13 2008
|
|
|
Search completed in 0.002 seconds
|
