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.

A088070 Numbers sandwiched between two numbers having the same number of prime divisors.

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%I A088070 #10 Feb 12 2018 04:29:07
%S A088070 3,4,6,8,10,11,12,13,18,19,21,23,24,25,26,27,28,30,34,35,37,39,42,45,
%T A088070 47,48,49,51,53,55,56,57,60,64,72,73,75,76,80,81,82,86,87,92,93,94,95,
%U A088070 97,99,102,105,107,108,116,117,118,123,126,131,134,135,138,139,142,143,144
%N A088070 Numbers sandwiched between two numbers having the same number of prime divisors.
%C A088070 Subsidiary sequence: (1) Start of the first run of a string of n successive integers in this sequence. Conjecture: For every k there is a string of k successive integers.
%H A088070 Giovanni Resta, <a href="/A088070/b088070.txt">Table of n, a(n) for n = 1..10000</a>
%F A088070 a(n) = A063464(n) + 1.
%e A088070 11 is a member as 10 and 12 both have two prime divisors.
%e A088070 26 is a member as 25 and 27 both have one each prime divisor.
%o A088070 (PARI) isok(n) = omega(n-1) == omega(n+1); \\ _Michel Marcus_, Oct 18 2016
%Y A088070 Cf. A063464.
%K A088070 nonn
%O A088070 1,1
%A A088070 _Amarnath Murthy_, Sep 22 2003
%E A088070 More terms from _Ray Chandler_, Sep 27 2003
%E A088070 Offset corrected and formula adapted by _Michel Marcus_, Oct 18 2016