

A085323


Numbers k such that both k and k+1 are sums of two positive cubes.


3



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
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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

Zak Seidov, Table of n, a(n) for n = 1..664


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
Adjacent sequences: A085320 A085321 A085322 * A085324 A085325 A085326


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



