A318251 Lesser of amicable numbers pair (m, n) such that n = H(m) and m = H(n) where H(n) = A074206(n) is the number of ordered factorizations of n.

6144, 19329024, 939524096, 4026531840, 309237645312, 6146186280960, 52158082842624, 29273397577908224

Offset

1,1

Comments

The larger numbers in each pair are in A318252.

Analogous to A002025 as A163272 is analogous to A000396.

If p and 4p+1 are primes then 2^(4p-1)*p is in this sequence, therefore if A023212 is infinite then also this sequence is.

The terms were calculated using an extended list of terms of A025487.

Links

Table of n, a(n) for n=1..8.

Example

6144 is in the sequence since A074206(6144) = 13312 and A074206(13312) = 6144.

Prog

(PARI) f(n) = if( n<2, n>0, my(A = divisors(n)); sum(k=1, #A-1, f(A[k])));
isok(n)={my(a=f(n)); a>n && f(a)==n; } \\ Michel Marcus, Sep 26 2018

Crossrefs

Cf. A023212, A074206, A090866, A163272, A318252.

Sequence in context: A251787 A203982 A204626 * A281265 A007992 A033288

Adjacent sequences: A318248 A318249 A318250 * A318252 A318253 A318254

Keyword

nonn,more

Author

Amiram Eldar, Aug 22 2018

Status

approved