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A187930 Least number r such that r == k-1 (mod prime(k)) for k = 1..n. 1

%I #9 Mar 24 2018 14:49:30

%S 0,4,22,52,1522,29242,299512,4383592,188677702,5765999452,5765999452,

%T 2211931390882,165468170356702,8075975022064162,361310530977154972,

%U 20037783573808880092,1779852341342071295512,40235059344426324076912,4966347076439519105374252,169991099649125127278835142

%N Least number r such that r == k-1 (mod prime(k)) for k = 1..n.

%H Harvey P. Dale, <a href="/A187930/b187930.txt">Table of n, a(n) for n = 1..350</a>

%F a(n) = A053664(n) - 1.

%e a(4) = 1522 because :

%e 1522 == 0 (mod 2) ;

%e 1522 == 1 (mod 3);

%e 1522 == 2 (mod 5);

%e 1522 == 3 (mod 7);

%e 1522 == 4 (mod 11).

%p with(numtheory):nn:=100:T:=array(1..nn):pr:=1:for k from 1 to nn do: pr:=pr*ithprime(k):T[k]:=pr:od:for m from 1 to nn do:z:=T[m]:pp:=ithprime(m):id:=0:for x from 0 to z-1 while (id=0) do:it:=0:for y from 0 to m-1 do:r:=ithprime(y+1):a:=irem(x,r):if a=y then it:=it+1:else

%p fi: od:if it =m then id:=1:print(x):else fi:od:od:

%t Table[ChineseRemainder[Range[n] - 1, Prime[Range[n]]], {n, 20}]

%Y Cf. A070198.

%K nonn

%O 1,2

%A _Michel Lagneau_, Mar 16 2011

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Last modified April 24 04:14 EDT 2024. Contains 371918 sequences. (Running on oeis4.)