A274384 - OEIS

A274384

Numbers n such that 2^n is not the average of three positive cubes.

1, 2, 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19, 20, 22, 23, 25, 26, 28, 29, 31, 32, 34, 37, 40, 43, 46

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OFFSET

1,2

COMMENTS

Numbers n such that 3*2^n = x^3 + y^3 + z^3 where x, y, z > 0, is not soluble.

Numbers n such that A007283(n) is not the sum of three positive cubes.

Sequence is finite because 47, 48, and 49 are not in the sequence and the absence of k from the sequence implies the absence of k+3. - Giovanni Resta, Jun 27 2016

LINKS

Table of n, a(n) for n=1..27.

EXAMPLE

47 is not a term because 2^47 = (8288^3 + 49808^3 + 66800^3) / 3.

49 is not a term because 2^49 = (13379^3 + 70082^3 + 110309^3) / 3.

CROSSREFS

Cf. A000079, A003072, A007283.

Sequence in context: A329925 A001651 A224999 * A195175 A248607 A191266

Adjacent sequences: A274381 A274382 A274383 * A274385 A274386 A274387

KEYWORD

nonn,fini,full

AUTHOR

Altug Alkan, Jun 19 2016

STATUS

approved