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.
%I A163588 #21 Feb 16 2025 22:37:21 %S A163588 2,3,5,17,37,101,197,257,401,577,677,1297,1601,2917,3137,4357,5477, %T A163588 7057,8101,8837,12101,13457,14401,15377,15877,16901,17957,21317,22501, %U A163588 24337,25601,28901,30977,32401,33857,41617,42437,44101,50177,52901,55697,57601,62501 %N A163588 Primes which are within 1 of a square number. %C A163588 The only prime of the form n^2 - 1 is 3. Remember that n^2 - 1 = (n - 1)(n + 1), so, for example, for n = 12, we have n^2 - 1 = 143 = 11 * 13. - _Alonso del Arte_, Feb 16 2025 %H A163588 David A. Corneth, <a href="/A163588/b163588.txt">Table of n, a(n) for n = 1..10000</a> (First 1000 terms from G. C. Greubel) %F A163588 {3} Union A002496. - _R. J. Mathar_, Aug 06 2009 %e A163588 6^2 + 1 = 37, which is prime, so 37 is in the sequence. %e A163588 8^2 + 1 = 65 = 5 * 13, so 65 is not in the sequence. %t A163588 Union[{3}, Select[Range[100]^2 + 1, PrimeQ]] (* _G. C. Greubel_, Jul 28 2017 *) %Y A163588 Cf. A002496, A002522. %K A163588 nonn,easy %O A163588 1,1 %A A163588 _Gaurav Kumar_, Jul 31 2009