A318252 Larger 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.

13312, 81551360, 1946157056, 128580583424, 12695923326976, 33590071001088, 2182874178519040, 59672695062659072

Offset

1,1

Comments

The lesser numbers in each pair are in A318251.

Analogous to A002046 as A163272 is analogous to A000396.

If p and 4p+1 are primes then 2^(4p-2)*(4p+1) is in this sequence.

Links

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

Example

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

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, A318251.

Sequence in context: A345840 A031620 A251339 * A034625 A283155 A254851

Adjacent sequences: A318249 A318250 A318251 * A318253 A318254 A318255

Keyword

nonn,more

Author

Amiram Eldar, Aug 22 2018

Status

approved