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A152044 Numbers expressible as the difference of two nonnegative fourth powers. 4
0, 1, 15, 16, 65, 80, 81, 175, 240, 255, 256, 369, 544, 609, 624, 625, 671, 1040, 1105, 1215, 1280, 1295, 1296, 1695, 1776, 2145, 2320, 2385, 2400, 2401, 2465, 2800, 3439, 3471, 3840, 4015, 4080, 4095, 4096, 4160, 4641, 5265, 5904, 5936, 6095, 6305, 6480 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Contains A000583 and A147857 as subsequences. - Chandler
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
E.g. 15=2^4-1^4, 175=4^4-3^4
MATHEMATICA
Select[Abs[Differences/@Tuples[Range[0, 12]^4, 2]]//Flatten//Union, #<= 6500&] (* Harvey P. Dale, Sep 14 2020 *)
PROG
(PARI) is(n)=if(n<1, return(!n)); for(m=sqrtnint(n-1, 4)+1, sqrtnint(n\4, 3)+1, if(ispower(m^4-n, 4), return(1))); 0 \\ Charles R Greathouse IV, Sep 04 2013
(PARI) lst(lim)=my(v=List([0]), t); lim\=1; for(n=1, sqrtnint(lim\4, 3)+1, for(m=sqrtnint(max(n^4-lim, 0), 4), n-1, t=n^4-m^4; if(t<=lim, listput(v, t)))); vecsort(Vec(v), , 8) \\ Charles R Greathouse IV, Sep 04 2013
CROSSREFS
Sequence in context: A041460 A041466 A332008 * A041468 A041470 A041472
KEYWORD
nonn
AUTHOR
Mark Taggart (mt2612f(AT)aol.com), Nov 21 2008
EXTENSIONS
Extended by Ray Chandler, Dec 04 2008
Definition corrected by Harvey P. Dale, Jan 19 2018
STATUS
approved

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Last modified March 28 07:48 EDT 2024. Contains 371235 sequences. (Running on oeis4.)