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 A260709 Smallest nonsquare congruent to a square (mod k^2) for all k = 1..n. 2
 2, 5, 13, 52, 241, 241, 436, 1009, 1009, 1009, 2641, 2641, 8089, 8089, 8089, 8089, 18001, 18001, 53881, 53881, 53881, 53881, 87481, 87481, 87481, 87481, 87481, 87481, 117049, 117049, 515761, 515761, 515761, 515761, 515761, 515761, 1083289, 1083289, 1083289, 1083289 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A variant of A081650 which uses the remainder modulo k^2 instead of the congruence (mod k^2). Suggested by Don Reble and R. Israel and the original title of A081650. LINKS Robert Israel and Emmanuel Vantieghem, Table of n, a(n) for n = 1..81[Terms 1 through 70 were computed by R. Israel: terms 71 through 82 by E. Vantieghem. Nov 23 2015] R. Israel in reply to Don Reble, A081650, SeqFan list, Nov. 17, 2015 MATHEMATICA (* to get the sequence up to B *) VQR=Table[Union[Mod[Range[(n^2)/2]^2, n^2]], {n, 2, 17}]; Print[2]; k=1; m=2; While[k 0), m^2];   nsq(sqs) = 0;   S = nsq * ones(1, ceil(N/m^2));   S = reshape(S, 1, numel(S));   B(S(1:N)>0) = 0;   v = find(B, 1, 'first');   if numel(v) == 0     break   end   A(m) = v;   m = m + 1; end A % Robert Israel, Nov 17 2015 CROSSREFS Cf. A081650. Sequence in context: A082938 A303792 A059103 * A112836 A105905 A236513 Adjacent sequences:  A260706 A260707 A260708 * A260710 A260711 A260712 KEYWORD nonn AUTHOR M. F. Hasler, Nov 17 2015 STATUS approved

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Last modified June 20 10:13 EDT 2019. Contains 324234 sequences. (Running on oeis4.)