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

Author

M. F. Hasler, Apr 13 2008

Keywords

• nonn

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.

Crossrefs

Cf. A024975 (a^3+b^3+c^3, a>b>c>0), A138854, A120398.

Programs

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", "))

Formula

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