cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A081649 Integers congruent to 0, 1, 4, 9, 16, 25, 36, 49, 64 or 81 (mod 100) which are not squares.

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%I A081649 #4 Jan 08 2019 18:17:38
%S A081649 101,104,109,116,125,136,149,164,181,200,201,204,209,216,236,249,264,
%T A081649 281,300,301,304,309,316,325,336,349,364,381,401,404,409,416,425,436,
%U A081649 449,464,481,500,501,504,509,516,525,536,549,564,581,600,601,604,609
%N A081649 Integers congruent to 0, 1, 4, 9, 16, 25, 36, 49, 64 or 81 (mod 100) which are not squares.
%D A081649 Mark A. Herkommer, Number Theory, A Programmer's Guide, McGraw-Hill, New York, 1999, page 315.
%t A081649 Select[ Range[615], (Mod[ #, 100] == 0 || Mod[ #, 100] == 1 || Mod[ #, 100] == 4 || Mod[ #, 100] == 9 || Mod[ #, 100] == 16 || Mod[ #, 100] == 25 || Mod[ #, 100] == 36 || Mod[ #, 100] == 49 || Mod[ #, 100] == 64 || Mod[ #, 100] == 81) && !IntegerQ[ Sqrt[ # ]] & ]
%t A081649 icQ[n_]:=!IntegerQ[Sqrt[n]]&&MemberQ[Range[0,9]^2,Mod[n,100]]; Select[ Range[ 700],icQ] (* _Harvey P. Dale_, Jan 08 2019 *)
%K A081649 easy,nonn
%O A081649 1,1
%A A081649 _Robert G. Wilson v_, Mar 26 2003