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A120398 Sums of two distinct prime cubes. 15
35, 133, 152, 351, 370, 468, 1339, 1358, 1456, 1674, 2205, 2224, 2322, 2540, 3528, 4921, 4940, 5038, 5256, 6244, 6867, 6886, 6984, 7110, 7202, 8190, 9056, 11772, 12175, 12194, 12292, 12510, 13498, 14364, 17080, 19026, 24397, 24416, 24514 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If an element of this sequence is odd, it must be of the form a(n)=8+p^3, else it is a(n)=p^3+q^3 with two primes p>q>2. - M. F. Hasler, Apr 13 2008

LINKS

M. F. Hasler, Table of n, a(n) for n = 1..284.

Index to sequences related to sums of cubes.

FORMULA

A120398 = (A030078 + A030078) - 2*A030078 = 8+(A030078\{8}) U { A030078(m)+A030078(n) ; 1<m<n } - M. F. Hasler, Apr 13 2008

EXAMPLE

2^3+3^3=35=a(1), 2^3+5^3=133=a(2), 3^3+5^3=152=a(3), 2^3+7^3=351=a(4).

MATHEMATICA

Select[Sort[ Flatten[Table[Prime[n]^3 + Prime[k]^3, {n, 15}, {k, n - 1}]]], # <= Prime[15^3] &]

PROG

(PARI) isA030078(n)=n==round(sqrtn(n, 3))^3 && isprime(round(sqrtn(n, 3)))  \\ M. F. Hasler, Apr 13 2008

(PARI) isA120398(n)={ n%2 & return(isA030078(n-8)); n<35 & return; forprime( p=ceil( sqrtn( n\2+1, 3)), sqrtn(n-26.5, 3), isA030078(n-p^3) & return(1))} \\ M. F. Hasler, Apr 13 2008

(PARI) for( n=1, 10^6, isA120398(n) & print1(n", ")) \\ - M. F. Hasler, Apr 13 2008

CROSSREFS

Subsequence of A024670.

Sequence in context: A220481 A144492 A192926 * A039522 A044367 A044748

Adjacent sequences:  A120395 A120396 A120397 * A120399 A120400 A120401

KEYWORD

nonn

AUTHOR

Tanya Khovanova, Jul 24 2007

STATUS

approved

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Last modified March 27 22:02 EDT 2017. Contains 284182 sequences.