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A327260
Odd numbers not of the form 2*n*k - n - k + 1 where n and k are odd numbers > 1.
3
1, 3, 5, 7, 9, 11, 15, 17, 19, 21, 25, 27, 29, 31, 35, 37, 39, 45, 47, 49, 51, 55, 57, 61, 65, 67, 69, 71, 75, 79, 81, 87, 89, 91, 97, 99, 101, 105, 107, 109, 115, 117, 119, 121, 125, 127, 129, 135, 139, 141, 147, 151, 155, 157, 159, 161, 165, 169
OFFSET
1,2
COMMENTS
Terms are the odd numbers not appearing in array A327259 with its first row and column omitted.
LINKS
MAPLE
N:= 201: # for terms <= N
f:= (n, k) -> 2*n*k-n-k+1:
S:= {seq(i, i=1..N, 2)} minus {seq(seq(f(n, k), k=3..min(N, (N+n-1)/(2*n-1)), 2), n=3..(N+2)/5, 2)}:
sort(convert(S, list)); # Robert Israel, Sep 09 2020
MATHEMATICA
Select[2 Range[100]-1, FindInstance[# == 1 + 2*n + k (2 + 8 n) && n>0 && k>0, {n, k}, Integers] === {} &] (* David Lovler, Dec 28 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
David Lovler, Aug 27 2019
EXTENSIONS
Corrected by Robert Israel, Sep 09 2020
STATUS
approved