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 A056808 #13 Jun 26 2025 07:59:33
%S A056808 18,54,90,108,150,162,270,300,324,450,486,540,600,630,648,750,810,972,
%T A056808 1050,1200,1350,1458,1470,1500,1620,1890,1944,2100,2250,2400,2430,
%U A056808 2700,2916,2940,3000,3150,3240,3750,3780,3888,4050,4200,4374,4410,4500,4800
%N A056808 Members of A055932 which are not least prime signatures (cf. A025487).
%H A056808 Michael De Vlieger, <a href="/A056808/b056808.txt">Table of n, a(n) for n = 1..10000</a>
%F A056808 {a(n) : n >= 1} = {A057335(A335485(k)) : k >= 1}. - _Peter Munn_, Feb 02 2024
%F A056808 Sum_{n>=1} 1/a(n) = A345974 - A161360 = 0.15229524564163275059... . - _Amiram Eldar_, Jun 26 2025
%e A056808 18 = 2*3*3 and all prime divisors are consecutive primes but the least prime signature is 12 = 2*2*3; so a(1) = 18.
%t A056808 With[{nn = 4800}, Select[Range[2, nn], And[#1 != Times @@ MapIndexed[Prime[First@ #2]^#1 &, Sort[#3, Greater]], Last[#2] == Prime@ Length[#2]] & @@ Apply[Join, {{#1}, Transpose@ #2}] & @@ {#, FactorInteger[#]} &] ] (* _Michael De Vlieger_, Feb 06 2020 *)
%Y A056808 Cf. A025487, A055932, A057335, A161360, A335485, A345974.
%K A056808 easy,nonn
%O A056808 1,1
%A A056808 _Alford Arnold_, Aug 22 2000
%E A056808 More terms from Larry Reeves (larryr(AT)acm.org), Nov 28 2000