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Search: id:A120398
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| A120398 |
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Sums of two distinct prime cubes. |
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+0
14
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| 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; listen)
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OFFSET
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1,1
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COMMENT
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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 (www.univ-ag.fr/~mhasler), Apr 13 2008
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LINKS
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M. F. Hasler, Table of n, a(n) for n=1,...,284.
Index to sequences related to sums of cubes.
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FORMULA
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A120398 = (A030078 + A030078) - 2*A030078 = 8+(A030078\{8}) U { A030078(m)+A030078(n) ; 1<m<n } - M. F. Hasler (www.univ-ag.fr/~mhasler), Apr 13 2008
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EXAMPLE
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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).
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MATHEMATICA
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Select[Sort[ Flatten[Table[Prime[n]^3 + Prime[k]^3, {n, 15}, {k, n - 1}]]], # <= Prime[15^3] &]
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PROGRAM
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(PARI) isA030078(n)={ n==round(sqrtn(n, 3))^3 & isprime(round(sqrtn(n, 3))) } - M. F. Hasler (www.univ-ag.fr/~mhasler), Apr 13 2008
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 (www.univ-ag.fr/~mhasler), Apr 13 2008
for( n=1, 10^6, isA120398(n) & print1(n", ")) \\ - M. F. Hasler (www.univ-ag.fr/~mhasler), Apr 13 2008
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CROSSREFS
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Subsequence of A024670.
Sequence in context: A044667 A132144 A098218 this_sequence A039522 A044367 A044748
Adjacent sequences: A120395 A120396 A120397 this_sequence A120399 A120400 A120401
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KEYWORD
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nonn
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AUTHOR
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Tanya Khovanova (tanyakh(AT)yahoo.com), Jul 24 2007
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