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 A146121 #16 Jun 21 2025 23:58:00 %S A146121 1,1,2,5,15,21,17,9,17,5,4,11,15,1,20,30,16,8,1,21,3,25,26,19,16,2,15, %T A146121 16,17,12,3,2,3,7,20,5,7,26,26,22,9,15,26,16,21,19,15,24,9,22,24,28, %U A146121 20,14,4,18,17,0,2,29,15,5,5,10,27,25,12,2,21,17,0,24,10,11,6,9,3,8,2,0,15,21 %N A146121 Bell numbers (A000110) read mod 31. %C A146121 Conjecture: a(n+568972471024107865287021434301977158534824481) = a(n). - _G. C. Greubel_, Feb 02 2016 [Conjecture is correct; see A054767. - _Jianing Song_, Jun 20 2025] %H A146121 G. C. Greubel, <a href="/A146121/b146121.txt">Table of n, a(n) for n = 0..10000</a> %H A146121 W. F. Lunnon, P. A. B. Pleasants, and N. M. Stephens, <a href="http://matwbn.icm.edu.pl/ksiazki/aa/aa35/aa3511.pdf">Arithmetic properties of Bell numbers to a composite modulus I</a>, Acta Arithmetica 35 (1979), pp. 1-16. %H A146121 <a href="/index/Rec#order_568972471024107865287021434301977158534824481">Index entries for linear recurrences with constant coefficients</a>, order 568972471024107865287021434301977158534824481. %t A146121 Mod[BellB[Range[0, 100]], 31] (* _G. C. Greubel_, Feb 02 2016 *) %o A146121 (Magma) [Bell(n) mod 31: n in [0..100]]; // _G. C. Greubel_, Feb 02 2016 %Y A146121 Cf. A000110, A146093-A146122 (Bell numbers read mod 3 to mod 32). %Y A146121 Cf. A054767 (periods). %K A146121 nonn %O A146121 0,3 %A A146121 _N. J. A. Sloane_, Feb 07 2009