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 A122842 #26 Jan 25 2025 03:11:05 %S A122842 1,3,9,27,15,243,729,45,6561,19683,135,177147,225,105,4782969, %T A122842 14348907,1215,675,387420489,3645,3486784401,10460353203,315, %U A122842 94143178827,3375,32805,2541865828329,6075,98415,68630377364883 %N A122842 Square roots of the odd indexed terms of A038547. %C A122842 A038547(n) is the least number with exactly n odd divisors. For odd n these are perfect squares. %H A122842 Amiram Eldar, <a href="/A122842/b122842.txt">Table of n, a(n) for n = 1..2100</a> (terms 1..1000 from R. J. Mathar) %F A122842 a(n) = sqrt(A038547(2*n-1)). %F A122842 a(n) = sqrt(A119265(2*n-1, 2*n-1)). %F A122842 a(n) = 3^(n-1) for n = (p+1)/2, where p is an odd prime. %F A122842 a(3*n+2) = 5*3^n for n = (p-1)/2, where p is an odd prime. %e A122842 a(1) = 1 because A038547(1) = 1. %e A122842 a(2) = 3 because A038547(3) = 9. %e A122842 a(5) = 15 because A038547(9) = 225. %t A122842 (* Function a038547[ ] is defined in A038547 *) %t A122842 a122842[n_]:=Sqrt[a038547[2n-1]] %t A122842 Map[a122842,Range[30]] (* _Hartmut F. W. Hoft_, Feb 07 2023 *) %Y A122842 Cf. A038547, A121858, A001227, A005179, A119265. %Y A122842 Cf. A007051, A070826, A002110. %K A122842 nonn %O A122842 1,2 %A A122842 _Alexander Adamchuk_, Sep 13 2006, Sep 25 2006 %E A122842 More terms from _R. J. Mathar_, Sep 20 2006 %E A122842 Edited by _Hartmut F. W. Hoft_, Feb 07 2023