A347384 - OEIS

%I #7 Sep 17 2021 16:16:05

%S 35,105,153,189,207,279,403,423,425,437,455,475,477,575,589,639,689,

%T 725,765,775,819,833,899,923,945,963,1025,1035,1071,1127,1143,1175,

%U 1209,1271,1275,1311,1325,1341,1365,1391,1395,1421,1425,1449,1475,1495,1519,1651,1719,1725,1739,1767,1775,1791,1881,1927,1953,1961

%N Odd numbers k with such a unitary divisor d that A347381(d) > A347381(k).

%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%e 35 is a product of two primes, 5 and 7, with A347381(7) = 3 > A347381(35) = 2, therefore 35 is included in this sequence.

%o (PARI) isA347384(n) = if(!(n%2),0,my(w=A347381(n)); fordiv(n,d,if(1==gcd(d,n/d) && (A347381(d)>w), return(1))); (0));

%Y Cf. A347381.

%Y Subsequences: A347390, A347383.

%K nonn

%O 1,1

%A _Antti Karttunen_, Sep 10 2021