cp's OEIS Frontend

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.

A136153 Composites one larger than a prime, with exactly four distinct prime factors.

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%I A136153 #11 Aug 15 2021 11:21:31
%S A136153 390,420,462,510,570,660,770,798,840,858,930,1020,1050,1092,1110,1218,
%T A136153 1230,1260,1290,1302,1320,1410,1428,1430,1482,1554,1560,1610,1638,
%U A136153 1710,1722,1848,1890,1914,1932,1950,1974,1980,2030,2040,2070,2090,2100,2130
%N A136153 Composites one larger than a prime, with exactly four distinct prime factors.
%H A136153 Harvey P. Dale, <a href="/A136153/b136153.txt">Table of n, a(n) for n = 1..2000</a>
%F A136153 Equals A008864 INTERSECT A033993. - _R. J. Mathar_, Feb 20 2008
%e A136153 a(0)=390 because 30 follows the prime 29 and has four prime factors 2, 3, 5 and 13.
%t A136153 Select[Prime[Range[400]]+1,PrimeNu[#]==4&] (* _Harvey P. Dale_, Aug 15 2021 *)
%o A136153 (PARI) isok(n) = (omega(n)==4) && isprime(n-1); \\ _Michel Marcus_, Jun 08 2014
%Y A136153 Cf. A136151, A136152, A136154, A136155.
%K A136153 easy,nonn
%O A136153 1,1
%A A136153 _Enoch Haga_, Dec 16 2007
%E A136153 Edited by _R. J. Mathar_, Feb 20 2008