

A051384


Sum of two (possibly negative) cubes in at least 4 ways.


3



2741256, 4118877, 6017193, 6742008, 9016488, 16776487, 21930048, 28699272, 32951016, 36875384, 42549416, 48137544, 48275136, 52324993, 53936064, 70957971, 72131904, 74013912, 87539319, 94287375, 102977784, 105651000, 111209679, 119824488, 122262264, 124454421, 134211896
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OFFSET

1,1


COMMENTS

This sequence is infinite, since if n is in the sequence so is n*k^3 for all k > 0; thus a(n) << n^3.  Charles R Greathouse IV, Nov 29 2014


LINKS



EXAMPLE

42549416 = 348^3+74^3 = 282^3+272^3 = (2662)^3+2664^3 = (475)^3+531^3, so 42549416 is in the sequence. (Silverman)


PROG

(PARI) T=thueinit('z^3+1); is(n)=my(v=thue(T, n)); #v>6 && #select(u>u[1]<=u[2], v)>3 \\ Charles R Greathouse IV, Nov 29 2014


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS

Missing terms 42549416, 48275136, 94287375, 111209679, 124454421 added by Rosalie Fay, Oct 13 2017


STATUS

approved



