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%I #15 Feb 19 2022 10:23:34
%S 26,74,122,146,194,218,234,314,362,386,458,482,554,626,650,666,674,
%T 698,746,794,818,842,866,914,1082,1098,1154,1202,1226,1314,1322,1346,
%U 1418,1466,1514,1538,1658,1706,1746,1754,1850,1874,1962,1994,2018,2042,2066,2106,2138,2186,2234,2258,2306,2402,2426,2474,2498
%N Numbers k such that both k and sigma(k) are congruent to 2 modulo 4 and the 3-adic valuation of sigma(k) is exactly 1.
%C All the terms of the form 4u+2 in A349745 (if they exist) are found in this sequence. As A351537 is the intersection of A191218 and A329963, and the latter has asymptotic density zero, so has this sequence also. It is conjectured that A351555(a(n)) is nonzero for all n, which would imply that the intersection with A349745 is empty. - _Antti Karttunen_, Feb 19 2022
%H Antti Karttunen, <a href="/A351538/b351538.txt">Table of n, a(n) for n = 1..25000</a>
%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F a(n) = 2 * A351537(n).
%o (PARI) isA351538(n) = if(!(2==(n%4)),0, my(s=sigma(n)); (2 == (s%4)) && (1==valuation(s,3)));
%Y Cf. A191218, A329963, A349745, A351537.
%Y Probably a subsequence of A351543. (See also A351550, A351555).
%K nonn
%O 1,1
%A _Antti Karttunen_, Feb 14 2022