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A361686
a(n) is the least totient divisor of A329872(n), where A329872 are nontotients (A005277) that are the product of two totients (A002202).
1
22, 22, 10, 46, 58, 46, 78, 82, 58, 46, 102, 22, 106, 82, 46, 138, 106, 82, 166, 172, 178, 190, 106, 226, 82, 166, 238, 172, 178, 22, 106, 262, 190, 282, 22, 106, 310, 316, 226, 82, 166, 238, 172, 346, 46, 178, 22, 358, 22, 10, 366, 106, 262, 382, 82, 388, 58, 22, 22, 46, 418
OFFSET
1,1
COMMENTS
Let k be the least instance a(k) = m, then A329872(k) = m*A361058(m). For instance a(3)=10, and A329872(3) = 1100 = 10*110 = 10*A361058(10).
Can we get a(k)=30 or a(k)=52 (see A361058)?
LINKS
EXAMPLE
a(3)=10 because A329872(3)=1100 which can be expressed as 1*1100, 2*550, 4*275, 5*220, 10*110, ... where 10*110 is the first case where both factors are nontotients.
PROG
(PARI) is(n) = if(!istotient(n), my(v=divisors(n)); for(i=1, (1+#v)\2, if(istotient(v[i])&&istotient(n/v[i]), return(1))); 0); \\ A329872
lista(nn) = for (n=1, nn, if (is(n), my(d=divisors(n)); for (i=1, (1+#d)\2, if (istotient(d[i]) && istotient(n/d[i]), print1(d[i], ", "); break); ); ); );
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Mar 29 2023
STATUS
approved