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%I #9 Feb 11 2020 03:54:19
%S 1,2,3,4,7,8,12,18,36,49,72,100,128,133,148,162,192,199,217,218,256,
%T 288,313,337,400,421,457,511,547,548,562,576,577,578,652,661,676,721,
%U 841,842,871,876,1058,1093,1152,1171,1191,1200,1227,1233,1249,1282,1306
%N Numbers k such that k and k+1 both have unique values of sigma(k) and sigma(k+1); sigma(k) = A000203(k) = sum of divisors of k.
%C Subsequence of A211656. Number k is in sequence iff k and k+1 are in A211656.
%H Amiram Eldar, <a href="/A211659/b211659.txt">Table of n, a(n) for n = 1..10000</a>
%e Number 36 is in sequence because sigma(36) = 91, sigma(37) = 38 and there are no other numbers m, n with sigma(m) = 91 or sigma(n) = 38.
%Y Cf. A000203, A211656, A211657, A211658, A211660.
%K nonn
%O 1,2
%A _Jaroslav Krizek_, Apr 20 2012