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 A073032 #10 Aug 18 2024 05:16:41 %S A073032 18048976,20100368,18914992,19252208,18048976,20100368,18914992, %T A073032 19252208,18048976,20100368,18914992,19252208,18048976,20100368, %U A073032 18914992,19252208,18048976,20100368,18914992,19252208,18048976,20100368,18914992,19252208,18048976 %N A073032 A 4-cycle of the k => sigma(k)-k process, where sigma(k) is the sum of divisors of k (A000203). %C A073032 18048976 = 2^4*11*102551, 20100368 = 2^4*919*1367, 18914992 = 2^4*37*89*359, 19252208 = 2^4*1203263. %C A073032 The cycle was discovered by Cohen (1970). - _Amiram Eldar_, Aug 18 2024 %H A073032 Henri Cohen, <a href="https://doi.org/10.1090/S0025-5718-1970-0271004-6">On amicable and sociable numbers</a>, Math. Comp., Vol. 24, No. 110 (1970), pp. 423-429. %H A073032 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,1). %o A073032 (PARI) a(n)=[19252208, 18048976, 20100368, 18914992][n%4+1] \\ _Charles R Greathouse IV_, Feb 19 2013 %Y A073032 Cf. A000203, A045477, A073033, A090615. %K A073032 nonn,easy %O A073032 1,1 %A A073032 _Miklos Kristof_, Aug 22 2002 %E A073032 Terms corrected by _Charles R Greathouse IV_, Feb 19 2013