

A137409


Numbers that cannot be the value of 'C' in a primitive Pythagorean triple (A < B; A^2 + B^2 = C^2).


6



1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 38, 39, 40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59, 60, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83
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OFFSET

1,2


COMMENTS

Complement of A008846.  R. J. Mathar, Aug 15 2010
A024362(a(n)) = 0.  Reinhard Zumkeller, Dec 02 2012
Except for the 1st term 1, complement of A004613.  Federico Provvedi, Jan 26 2019


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


EXAMPLE

3,4,5; number 5 is not in this sequence.
5,12,13; number 13 is not in this sequence.
8,15,17; number 17 is not in this sequence.
7,24,25; number 25 is not in this sequence.


MATHEMATICA

okQ[1] = True;
okQ[n_] := AnyTrue[FactorInteger[n][[All, 1]], Mod[#, 4] != 1&];
Select[Range[100], okQ] (* JeanFrançois Alcover, Mar 10 2019, after Federico Provvedi's comment *)


PROG

(Haskell)
import Data.List (elemIndices)
a137409 n = a137409_list !! (n1)
a137409_list = map (+ 1) $ elemIndices 0 a024362_list
 Reinhard Zumkeller, Dec 02 2012


CROSSREFS

Cf. A137407, A020882.
Sequence in context: A035058 A004776 A187945 * A037041 A048263 A141451
Adjacent sequences: A137406 A137407 A137408 * A137410 A137411 A137412


KEYWORD

nonn


AUTHOR

Vladimir Joseph Stephan Orlovsky, Apr 14 2008


EXTENSIONS

Extended by R. J. Mathar, Aug 15 2010


STATUS

approved



