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 A258600 #20 Sep 11 2024 00:32:48 %S A258600 2,4,8,13,23,29,39,45,57,75,81,99,110,117,130,149,169,176,197,209,212, %T A258600 236,250,270,295,309,317,328,337,354,399,414,436,445,477,483,506,529, %U A258600 541,563,585,591,631,635,654,657,697,747,758,765,781,803,809,845,864 %N A258600 a(n) is the index m such that A036966(m) = prime(n)^3. %H A258600 Amiram Eldar, <a href="/A258600/b258600.txt">Table of n, a(n) for n = 1..1000</a> %F A258600 A036966(a(n)) = A030078(n) = prime(n)^3. %F A258600 A036966(m) mod prime(n) > 0 for m < a(n). %F A258600 Also smallest number m such that A258568(m) = prime(n): %F A258600 A258568(a(n)) = A000040(n) and A258568(m) != A000040(n) for m < a(n). %e A258600 . n | p | a(n) | A036966(a(n)) = A030078(n) = p^3 %e A258600 . ----+----+-------+--------------------------------- %e A258600 . 1 | 2 | 2 | 8 %e A258600 . 2 | 3 | 4 | 27 %e A258600 . 3 | 5 | 8 | 125 %e A258600 . 4 | 7 | 13 | 343 %e A258600 . 5 | 11 | 23 | 1331 %e A258600 . 6 | 13 | 29 | 2197 %e A258600 . 7 | 17 | 39 | 4913 %e A258600 . 8 | 19 | 45 | 6859 %e A258600 . 9 | 23 | 57 | 12167 %e A258600 . 10 | 29 | 75 | 24389 %e A258600 . 11 | 31 | 81 | 29791 %e A258600 . 12 | 37 | 99 | 50653 %e A258600 . 13 | 41 | 110 | 68921 %e A258600 . 14 | 43 | 117 | 79507 %e A258600 . 15 | 47 | 130 | 103823 %e A258600 . 16 | 53 | 149 | 148877 %e A258600 . 17 | 59 | 169 | 205379 %e A258600 . 18 | 61 | 176 | 226981 %e A258600 . 19 | 67 | 197 | 300763 %e A258600 . 20 | 71 | 209 | 357911 %e A258600 . 21 | 73 | 212 | 389017 %e A258600 . 22 | 79 | 236 | 493039 %e A258600 . 23 | 83 | 250 | 571787 %e A258600 . 24 | 89 | 270 | 704969 %e A258600 . 25 | 97 | 295 | 912673 . %t A258600 With[{m = 60}, c = Select[Range[Prime[m]^3], Min[FactorInteger[#][[;; , 2]]] > 2 &]; 1 + Flatten[FirstPosition[c, #] & /@ (Prime[Range[m]]^3)]] (* _Amiram Eldar_, Feb 07 2023 *) %o A258600 (Haskell) %o A258600 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A258600 a258600 = (+ 1) . fromJust . (`elemIndex` a258568_list) . a000040 %o A258600 (Python) %o A258600 from math import gcd %o A258600 from sympy import prime, integer_nthroot, factorint %o A258600 def A258600(n): %o A258600 c, m = 0, prime(n)**3 %o A258600 for w in range(1,integer_nthroot(m,5)[0]+1): %o A258600 if all(d<=1 for d in factorint(w).values()): %o A258600 for y in range(1,integer_nthroot(z:=m//w**5,4)[0]+1): %o A258600 if gcd(w,y)==1 and all(d<=1 for d in factorint(y).values()): %o A258600 c += integer_nthroot(z//y**4,3)[0] %o A258600 return c # _Chai Wah Wu_, Sep 10 2024 %Y A258600 Cf. A258568, A000040, A030078, A036966, A258599, A258601, A258602, A258603. %K A258600 nonn %O A258600 1,1 %A A258600 _Reinhard Zumkeller_, Jun 06 2015 %E A258600 a(11)-a(55) and example corrected by _Amiram Eldar_, Feb 07 2023