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 A124663 Number of reduced infinitary amicable pairs (i,j) with i
 0, 0, 0, 1, 2, 3, 14, 25, 51, 112, 213 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS A divisor of n is called infinitary if it is a product of divisors of the form p^{y_a 2^a}, where p^y is a prime power dividing n and sum_a y_a 2^a is the binary representation of y. LINKS Pedersen J. M., Known amicable pairs. FORMULA Reduced infinitary amicable pairs (m,n) satisfy isigma(m)=isigma(n)=m+n+1, with m 1, True, False]; ReducedInfinitaryAmicablePairList[k_] := (anlist = Select[Range[k], ReducedInfinitaryAmicableNumberQ[ # ] &]; prlist = Table[Sort[{anlist[[n]], properinfinitarydivisorsum[anlist[[n]]] - 1}], {n, 1, Length[anlist]}]; amprlist = Union[prlist, prlist]); data1 = ReducedInfinitaryAmicablePairList[10^7]; Table[Length[Select[data1, First[ # ] < 10^k &]], {k, 1, 7}] CROSSREFS Cf. A126169, A049417, A126168, A037445, A126170, A126171, A126172, A126173, A126174, A126175, A126176. Sequence in context: A089876 A025092 A112636 * A101005 A029998 A117461 Adjacent sequences:  A124660 A124661 A124662 * A124664 A124665 A124666 KEYWORD hard,nonn AUTHOR Ant King, Dec 23 2006 STATUS approved

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Last modified October 21 23:02 EDT 2018. Contains 316431 sequences. (Running on oeis4.)