A323759 Larger of modified exponential amicable pairs.

126, 378, 1260, 3780, 4584, 5544, 11424, 16632, 16728, 49308, 68760, 73962, 88608, 179118, 168730, 212160, 225096, 256338, 266568, 250920, 365700, 374304, 391656, 374418, 387720, 386568, 393528, 548550, 827700, 739620, 827652, 932100, 912288, 935400, 1052088

Offset

1,1

Comments

A modified exponential amicable pair (m, n) has A241405(m) = A241405(n) = m + n + 1.

The lesser counterparts are in A323758.

Links

Amiram Eldar, Table of n, a(n) for n = 1..4725 (terms whose lesser counterparts below 2*10^11)

David Moews, Perfect, amicable and sociable numbers.

Mathematica

f[p_, e_] := DivisorSum[e+1, p^(#-1)&]; mesigma[1]=1; mesigma[n_] := Times @@ f @@@FactorInteger@ n; s={}; mes[n_] := mesigma[n]-n; Do[m=mes[n]; If[m>n && mes[m]==n, AppendTo[s, m]], {n, 1, 10000}]; s

Prog

(PARI) f(n) = {my(f=factor(n)); prod(i=1, #f[, 1], sumdiv(f[i, 2]+1, d, f[i, 1]^(d-1))); } \\ A241405
fm(n) = f(n) - n;
isok(n) = my(fn=fm(n)); (fn > 0) && (fn < n) && (fm(fn) == n); \\ Michel Marcus, Jan 30 2019

Crossrefs

Cf. A241405, A323757, A323758.

Sequence in context: A181255 A329807 A322542 * A102805 A267556 A268119

Adjacent sequences: A323756 A323757 A323758 * A323760 A323761 A323762

Keyword

nonn

Author

Amiram Eldar, Jan 26 2019

Status

approved