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 A138855 Half-sum (or average) of cubes of two distinct odd primes. 1
 76, 185, 234, 679, 728, 837, 1112, 1161, 1270, 1764, 2470, 2519, 2628, 3122, 3443, 3492, 3555, 3601, 4095, 4528, 5886, 6097, 6146, 6255, 6749, 7182, 8540, 9513, 12208, 12257, 12366, 12860, 13293, 14651, 14909, 14958, 15067, 15561, 15624, 15994 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Even terms of A120398, divided by two. (Terms in A120398 are even iff they are the sum of two odd prime cubes.) Also, even terms of A138854 divided by two minus 4 LINKS Table of n, a(n) for n=1..40. Index to sequences related to sums of cubes. FORMULA A138855 = { ( prime(i)^3+prime(j)^3 )/2 ; i>j>1 } = (1/2) { even terms in A120398 } = { even terms in A138854 } / 2 - 4. MATHEMATICA With[{nn=40}, Take[Union[Mean/@(Subsets[Prime[Range[2, nn/2]], {2}]^3)], nn]] (* Harvey P. Dale, Nov 16 2013 *) PROG (PARI) for(n=1, 10^5, isA120398(2*n) & print1(n", ")) CROSSREFS Cf. A120398, A138854. Sequence in context: A044408 A044789 A245005 * A324632 A251078 A153676 Adjacent sequences: A138852 A138853 A138854 * A138856 A138857 A138858 KEYWORD nonn AUTHOR M. F. Hasler, Apr 13 2008 STATUS approved

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Last modified September 7 20:21 EDT 2024. Contains 375749 sequences. (Running on oeis4.)