cp's OEIS Frontend

A236025 Composite numbers n sorted by increasing values of delta(n) = (n+1)^(1/2) - sigma(n)^(1/tau(n)), where sigma(n) = A000203(n) = the sum of divisors of n and tau(n) = A000005(n) = the number of divisors of n.

%I A236025 #6 Jan 21 2014 08:18:35
%S A236025 4,6,9,8,10,14,15,12,25,16,21,22,18,26,20,27,33,34,49,24,35,28,38,39,
%T A236025 32,30,46,51,36,55,58,44,57,40,45,42,62,50,65,52,69,48,74,54,77,56,82,
%U A236025 63,86,121,85,64,68,87,60,94,66,93,91,81,75,95,76,70,106,78
%N A236025 Composite numbers n sorted by increasing values of delta(n) = (n+1)^(1/2) - sigma(n)^(1/tau(n)), where sigma(n) = A000203(n) = the sum of divisors of n and tau(n) = A000005(n) = the number of divisors of n.
%C A236025 The number delta(n) = (n+1)^(1/2) - sigma(n)^(1/tau(n)) is called the delta-deviation from primality of the number n; delta(p) = 0 for p = prime.
%C A236025 For number 4; delta(4) = (4+1)^(1/2) - sigma(4)^(1/tau(4)) = 5^(1/2) - 7^(1/3) = 0.32313679472... = A236027 (minimal value of function delta(n)).
%C A236025 See A234516, A234520 and A236022 for definitions of functions alpha(n), beta(n) and gamma(n).
%C A236025 See A236026 - sequence of numbers a(n) such that a(n) > a(k) for all k < n.
%C A236025 Conjecture: Every natural number n has a unique value of number delta(n).
%H A236025 Jaroslav Krizek, <a href="/A236025/b236025.txt">Table of n, a(n) for n = 1..1000</a>
%Y A236025 Cf. A236020, A236021, A236022, A236023, A236024, A236026, A236027.
%K A236025 nonn
%O A236025 1,1
%A A236025 _Jaroslav Krizek_, Jan 19 2014