This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A141164 Numbers having exactly 1 divisor of the form 8*k + 7. 4

%I

%S 7,14,15,21,23,28,30,31,35,39,42,45,46,47,49,55,56,60,62,69,70,71,75,

%T 77,78,79,84,87,90,91,92,93,94,95,98,103,110,111,112,115,117,120,124,

%U 127,133,138,140,141,142,143,147,150,151,154,155,156,158,159,167,168,174,180,182,183,184,186,188,190,191,196,199

%N Numbers having exactly 1 divisor of the form 8*k + 7.

%C A188172(a(n)) = 1;

%C A007522 is a subsequence.

%H _Reinhard Zumkeller_, <a href="/A141164/b141164.txt">Table of n, a(n) for n = 1..10000</a>

%e a(1) = A188226(1) = 7.

%t okQ[n_] := Length[Select[Divisors[n] - 7, Mod[#, 8] == 0 &]] == 1; Select[Range[200], okQ]

%o (Haskell)

%o import Data.List (elemIndices)

%o a141164 n = a141164_list !! (n-1)

%o a141164_list = map succ \$ elemIndices 1 \$ map a188172 [1..]

%Y Cf. A004771.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Mar 26 2011

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified June 19 07:51 EDT 2013. Contains 226399 sequences.