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A137895 Products of two or more consecutive numbers that do not have prime gaps in their factorizations. 3

%I #9 Nov 14 2021 01:21:57

%S 2,6,12,24,30,60,72,90,120,210,240,360,420,600,720,840,1260,1680,2520,

%T 3360,5040,6480,6720,9240,15120,15750,20160,30240,40320,50400,55440,

%U 60480,117600,147840,151200,166320,181440,194040,240240,291060,332640

%N Products of two or more consecutive numbers that do not have prime gaps in their factorizations.

%C Intersection of A045619 and A073491; A000142 is a subsequence apart from initial terms.

%H David A. Corneth, <a href="/A137895/b137895.txt">Table of n, a(n) for n = 1..193</a>

%e a(10) = 210 = 2 * 3 * 5 * 7 = 5 * (5+1) * (5+2);

%e a(11) = 240 = 2^4 * 3 * 5 = 15 * (15+1);

%e a(12) = 360 = 2^3 * 3^2 * 5 = 3 * (3+1) * (3+2) * (3+3);

%e a(13) = 420 = 2^2 * 3 * 5 * 7 = 20 * (20+1);

%e a(14) = 600 = 2^3 * 3 * 5^2 = 24 * (24+1);

%e a(15) = 720 = 2^4 * 3^2 * 5 = 6!.

%Y Subsequence of A055932.

%Y Cf. A045619, A073491, A000142.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Feb 20 2008

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Last modified April 25 05:56 EDT 2024. Contains 371964 sequences. (Running on oeis4.)