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A004831 Numbers that are the sum of at most 2 nonzero 4th powers. 6
0, 1, 2, 16, 17, 32, 81, 82, 97, 162, 256, 257, 272, 337, 512, 625, 626, 641, 706, 881, 1250, 1296, 1297, 1312, 1377, 1552, 1921, 2401, 2402, 2417, 2482, 2592, 2657, 3026, 3697, 4096, 4097, 4112, 4177, 4352, 4721, 4802, 5392, 6497, 6561, 6562, 6577, 6642 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Apart from 0, 1, 2, there are no three consecutive terms up to 10^16. The first two consecutive terms not of the form n^4, n^4+1 are 3502321 = 25^4 + 42^4, 3502322 = 17^4 + 43^4. - Charles R Greathouse IV, Oct 17 2017

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

MATHEMATICA

Reap[For[n = 0, n < 10000, n++, If[MatchQ[ PowersRepresentations[n, 2, 4], {{_, _}, ___}], Print[n]; Sow[n]]]][[2, 1]] (* Jean-Fran├žois Alcover, Oct 30 2017 *)

PROG

(Haskell)

a004831 n = a004831_list !! (n-1)

a004831_list = [x ^ 4 + y ^ 4 | x <- [0..], y <- [0..x]]

-- Reinhard Zumkeller, Jul 15 2013

(PARI) is(n)=#thue(thueinit(z^4+1), n) \\ Ralf Stephan, Oct 18 2013

(PARI) list(lim)=my(v=List(), t); for(m=0, sqrtnint(lim\=1, 4), for(n=0, min(sqrtnint(lim-m^4, 4), m), listput(v, n^4+m^4))); Set(v) \\ Charles R Greathouse IV, Sep 28 2015

CROSSREFS

Subsequences include A000583 and A002645.

Sequence in context: A261617 A075376 A032935 * A217307 A282408 A282838

Adjacent sequences:  A004828 A004829 A004830 * A004832 A004833 A004834

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified June 15 22:19 EDT 2019. Contains 324145 sequences. (Running on oeis4.)