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 A087025 #19 Jul 07 2023 21:22:22 %S A087025 255360,17205180696931968,1951532915603927040,12430490030984319840000, %T A087025 9956179688423375044684800000, %U A087025 6080633705911286890368486450696472902951229440,4809378729404888733987843426081300724182624228548100710400 %N A087025 Sum of divisors of n-th cyclic number. %C A087025 Calculated with Dario Alpern's ECM. %C A087025 Extended using factors of 10^(A001913(n)-1)-1, see Kamada link. %H A087025 Max Alekseyev, <a href="/A087025/b087025.txt">Table of n, a(n) for n = 1..51</a> (first 42 terms from Ray Chandler) %H A087025 Dario A. Alpern, <a href="https://www.alpertron.com.ar/ECM.HTM">Factorization using the Elliptic Curve Method</a>. %H A087025 Makoto Kamada, <a href="https://stdkmd.net/nrr/repunit/">Factorizations of 11...11 (Repunit)</a> %H A087025 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CyclicNumber.html">Cyclic Number</a> %H A087025 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DivisorFunction.html">Divisor Function</a> %F A087025 a(n) = A000203(A004042(n+1)). %Y A087025 Cf. A001913, A087020, A087021, A087022, A087023, A087024, A087026. %K A087025 nonn %O A087025 1,1 %A A087025 _Reinhard Zumkeller_, Jul 30 2003 %E A087025 a(12)-a(42) from _Ray Chandler_, Nov 16 2011