A138853 Numbers which are the sum of 3 cubes of distinct odd primes.

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

Offset

1,1

Comments

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.

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000 (terms 1..560 from R. J. Mathar)

Index to sequences related to sums of cubes.

Formula

A138853={ p(i)^3+p(j)^3+p(k)^3 ; i>j>k>1 }

Prog

(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), A138854, A120398.

Sequence in context: A059828 A160851 A031898 * A164716 A164718 A151965

Adjacent sequences: A138850 A138851 A138852 * A138854 A138855 A138856

Keyword

nonn

Author

M. F. Hasler, Apr 13 2008

Status

approved