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 A066505 f-amicable numbers where f(n) = n+1. 0
 36, 62, 168, 326, 9936, 14056, 16198, 19862, 45304, 51910, 82662, 90152, 337688, 388102, 472902, 479672, 1970586, 2353756, 2969288, 3769942, 6319544, 8454886, 12276056, 13125574, 16783976, 17948854, 18818780, 20825882, 21738114, 22479040, 25960468, 31470614 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS f-amicable pairs are defined similarly to f-perfect numbers in A066218. That is, a, b is a f-amicable pair if f(a) = D(b) and f(b) = D(a), where D(n) = sum_{k divides n, k #include #include using namespace std ; inline int f(const int n) { return n+1 ; } int D(const int n) { int resul=0 ; for(int k=1 ; k < n ; k++) if ( n %k == 0) resul += k+1 ; return resul ; } int main(int argc, char *argv[]) { vector fvec ; vector Dvec ; fvec.push_back(1) ; Dvec.push_back(1) ; for(int a=1 ; a < INT_MAX ; a++) { fvec.push_back( f(a)) ; Dvec.push_back( D(a)) ; for(int b=1 ; b< a ; b++) { if ( fvec[a]==Dvec[b] && fvec[b] == Dvec[a]) cout << b << ", " << a << ", " ; } } return 0 ; } - R. J. Mathar, Sep 07 2006 CROSSREFS Cf. A066229, A066218. Sequence in context: A328961 A335295 A287862 * A039419 A043242 A044022 Adjacent sequences: A066502 A066503 A066504 * A066506 A066507 A066508 KEYWORD nonn AUTHOR Joseph L. Pe, Jan 04 2002 EXTENSIONS More terms from John W. Layman, Nov 11 2002 More terms from R. J. Mathar, Sep 07 2006 a(17)-a(32) from Donovan Johnson, Jun 23 2012 STATUS approved

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Last modified June 24 19:44 EDT 2024. Contains 373690 sequences. (Running on oeis4.)