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A085323 Numbers k such that both k and k+1 are sums of two positive cubes. 4
854, 4940, 9603, 10744, 17919, 29743, 62558, 79001, 133273, 164304, 193192, 205406, 214984, 242648, 263871, 378936, 431999, 447336, 488375, 517427, 610687, 731158, 762047, 1000511, 1061550, 1125207, 1134124, 1157632, 1158137, 1179520 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
There are 664 terms < 8*10^9, a(664)=7999968373. - Zak Seidov, Jul 24 2009
This is an infinite sequence. To see why, consider the (N,N+1) pair N = 16*k^6 - 12*k^4 + 6*k^2 - 2 = (2*k^2 - k - 1)^3 + (2*k^2 + k -1)^3 and N + 1 = 16*k^6 - 12*k^4 + 6*k^2 - 1 = (2*k^2)^3 + (2*k^2 - 1)^3. - Ant King, Sep 20 2013
LINKS
EXAMPLE
854 = 9^3 + 5^3 and 855 = 8^3 + 7^3;
4940 = 17^3 + 3^3 and 4941 = 13^3 + 14^3.
MATHEMATICA
{m=100, k=3, m^k}; t=Union[Flatten[Table[Table[w^k+q^k, {w, 1, m}], {q, 1, m}]]]; dt=Delete[ -RotateRight[t]+t, 1]; p=Part[t, Flatten[Position[dt, 1]]]; p
CROSSREFS
Cf. A003325.
Sequence in context: A127593 A248856 A251050 * A185639 A105275 A100969
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 01 2003
EXTENSIONS
Corrected and extended by Zak Seidov, Jul 24 2009
Name and Example edited by Jon E. Schoenfield, Jul 29 2017
STATUS
approved

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Last modified March 29 09:14 EDT 2024. Contains 371268 sequences. (Running on oeis4.)