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 A375964 #14 Sep 20 2024 06:27:06
%S A375964 41614,51358,55166,67066,97054,97294,100834,101914,109838,122758,
%T A375964 126634,130646,133286,148394,154582,175594,180214,180454,184666,
%U A375964 197086,212486,224258,226654,227446,231386,242906,258446,276394,284866,285086,300182,305066,308606,309506,317054,344434,350206,352834,360634,362594
%N A375964 Semiprime numbers that are sandwiched between products of exactly 4 distinct primes (or tetraprimes).
%F A375964 a(n) == 2 (mod 4).
%e A375964 41614 = 2 * 20807 (between 41613 = 3*11*13*97 and 41615 = 5*7*29*41).
%e A375964 51358 = 2 * 25679 (between 51357 = 3*17*19*53 and 51359 = 7*11*23*29).
%e A375964 55166 = 2 * 27583 (between 55165 = 5*11*17*59 and 55167 = 3*7*37*71).
%t A375964 e[n_] := FactorInteger[n][[;; , 2]]; SequencePosition[e /@ Range[400000], {{1, 1, 1, 1}, {1, 1}, {1, 1, 1, 1}}][[;; , 1]] + 1 (* _Amiram Eldar_, Sep 04 2024 *)
%Y A375964 Cf. A006881, A046386.
%Y A375964 Subsequence of A100484.
%K A375964 nonn
%O A375964 1,1
%A A375964 _Massimo Kofler_, Sep 04 2024