login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A169822 Numbers n such that A(n+1) = A(n) + 1, where A() = A005101() are the abundant numbers. 5

%I

%S 1432,1487,1849,2742,5380,5434,6474,6786,9752,10674,12311,14115,14557,

%T 15237,17266,17558,18987,19138,19761,20110,20259,20343,20967,20997,

%U 22262,22735,24342,25650,26003,26471,27122,27721,28914,28968,29741

%N Numbers n such that A(n+1) = A(n) + 1, where A() = A005101() are the abundant numbers.

%C A096399 is the main entry for this sequence.

%H Muniru A Asiru, <a href="/A169822/b169822.txt">Table of n, a(n) for n = 1..7000</a>

%p with(numtheory): A:=select(n->sigma(n)>2*n,[$1..150000]):

%p a:=select(j->A[j+1]=A[j]+1,[$1..nops(A)-1]); # _Muniru A Asiru_, Jun 10 2018

%t fQ[n_] := DivisorSigma[1, n] > 2 n; lst = {}; c = 0; k = 1; While[k < 125000, If[fQ@k, c++; If[fQ[k - 1], AppendTo[lst, c - 1]]]; k++ ]; lst (* _Robert G. Wilson v_, Jun 11 2010 *)

%o (GAP) A:=Filtered([1..150000],n->Sigma(n)>2*n);;

%o a:=Filtered([1..Length(A)-1],i->A[i+1]=A[i]+1); # _Muniru A Asiru_, Jun 10 2018

%Y Cf. A005101, A096399.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, May 29 2010

%E a(10) onwards from _Robert G. Wilson v_, Jun 11 2010

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 18 07:59 EDT 2021. Contains 343084 sequences. (Running on oeis4.)