A147857 Differences of two positive 4th powers.

0, 15, 65, 80, 175, 240, 255, 369, 544, 609, 624, 671, 1040, 1105, 1215, 1280, 1295, 1695, 1776, 2145, 2320, 2385, 2400, 2465, 2800, 3439, 3471, 3840, 4015, 4080, 4095, 4160, 4641, 5265, 5904, 5936, 6095, 6305, 6480, 6545, 6560, 7599, 7825, 8080, 8704

Offset

1,2

Comments

If n belongs to this sequence then so does n*m^4 for any positive integer m. Primitive elements (i.e., not of the form n*m^4 for m>1) are listed in A147858.

There is no square in this sequence except 0. - Altug Alkan, Apr 08 2016

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

N:= 10^4: # to get all terms <= N
Res:= {0}:
for a from 1 to floor(sqrt(N-2)) do
  if a^4 > N then bmin:= ceil((a^4-N)^(1/4)) else bmin:= 1 fi;
  Res:= Res union {seq(a^4-b^4, b=bmin..a-1)}
od:
sort(convert(Res, list)); # Robert Israel, Sep 28 2018

Mathematica

nn = 50; Take[Union @@ Map[Differences, Union@ Map[Sort@ # &, Tuples[Range[Ceiling[nn/3]], {2}]]^4], nn] (* Michael De Vlieger, Apr 09 2016 *)

Crossrefs

Cf. A147854, A147856, A147858

Sequence in context: A118531 A144710 A096905 * A147858 A364401 A005917

Adjacent sequences: A147854 A147855 A147856 * A147858 A147859 A147860

Keyword

nonn

Author

Max Alekseyev, Nov 15 2008, Nov 19 2008

Extensions

Offset changed by Robert Israel, Sep 28 2018

Status

approved