%I #31 Oct 21 2014 03:21:43
%S 40,85,393,625,1557,2106,4069,9558,11476,22060,31530,35998,49142,
%T 76678,113799,125010,176824,216378,234064,313511,372054,481764,668344,
%U 768307,811635,926452,975785,1105924,1751993,1949976,2299392,2394921,3130534,3250605,3751262,4306910,4683674,5332960
%N Number of numbers k in interval [(p_n)^2+1, (p_n)^4] for which lpf(k-3)>lpf(k-1)>=p_n, where p_n=prime(n) and lpf = A020639.
%C a(n) and A243804(n) approximate each other with a small relative error.
%C Positions n for which a(n) < A243804(n) are 11, 13, 14, 17, 18, 19, 20 (...).
%Y Cf. A020639 (lpf), A242719, A242720, A242847, A242758, A243804.
%K nonn
%O 3,1
%A _Vladimir Shevelev_ and _Peter J. C. Moses_, Jun 10 2014