

A303744


Numbers that are not a difference between same powers (greater than 1) of positive numbers.


2



1, 2, 4, 6, 10, 14, 18, 22, 30, 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 90, 94, 102, 106, 110, 114, 118, 122, 126, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190, 194, 198, 202, 206, 210, 214, 222, 226, 230, 234, 238, 246, 250, 254, 258, 262, 266, 270, 274, 278, 282, 286, 290
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OFFSET

1,2


COMMENTS

Apart from 1 and 4, all terms == 2 (mod 4).  Robert Israel, Jun 25 2018


LINKS

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


EXAMPLE

Odd numbers greater than 1 are differences of squares, so they are not here.
8 is not a term, 9  1: difference of two squares;
26 is not a term, 27  1: difference of two cubes.


MAPLE

N:= 1000: # to get all terms <= N
S:= {1, 2, 4, seq(i, i=6..N, 4)}:
for p from 3 to ilog2(N+1) do
for n from 1 while n^p  (n1)^p <= N do
if n^p > N then m0:= ceil((n^p  N)^(1/p)) else m0:= 1 fi;
for m from m0 to n1 do
v:= n^pm^p;
S:= S minus {v};
od
od od:
sort(convert(S, list)); # Robert Israel, Jun 25 2018


CROSSREFS

Sequences of numbers that are difference of powers: A024352 (squares), A181123 (cubes).
And of further nth powers: A147857 (4th), A181124 (5th), A181125 (6th), A181126 (7th), A181127 (8th), A181128 (9th).
Sequence in context: A062091 A100143 A234941 * A059254 A024518 A128422
Adjacent sequences: A303741 A303742 A303743 * A303745 A303746 A303747


KEYWORD

nonn


AUTHOR

Adam Kertesz, Apr 29 2018


STATUS

approved



