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Primes p such that p-1 is a product of two or more consecutive integers. Or (p-1) is a permutation of m items chosen from n, for some m and n. p-1 = k*(k+1)(k+2)...(k+r) for some k and r, r>0.
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%I #9 Aug 23 2014 15:07:33

%S 3,7,13,31,43,61,73,157,211,241,307,337,421,463,601,757,991,1123,1321,

%T 1483,1723,2521,2551,2731,2971,3307,3361,3541,3907,4423,4831,5113,

%U 5701,6007,6163,6481,6841,8011,8191,9241,9901,10303,10627,11131,12211,12433

%N Primes p such that p-1 is a product of two or more consecutive integers. Or (p-1) is a permutation of m items chosen from n, for some m and n. p-1 = k*(k+1)(k+2)...(k+r) for some k and r, r>0.

%H R. J. Mathar, <a href="/A083520/b083520.txt">Table of n, a(n) for n = 1..131</a>

%e 61 is in this sequence as 60 = 3*4*5. 73 is in this sequence as 72 = 8*9.

%p isA083520 := proc(p)

%p local k,r,i,po;

%p for k from 1 to floor(sqrt(p)) do

%p for r from 1 do

%p po := product(k+i,i=0..r) ;

%p if po = p-1 then

%p return true;

%p elif po > p-1 then

%p break;

%p end if;

%p end do:

%p end do:

%p false ;

%p end proc:

%p n := 1 :

%p for c from 1 do

%p p := ithprime(c) ;

%p if isA083520(p) then

%p printf("%d %d\n",n,p) ;

%p n := n+1 ;

%p end if;

%p end do: # _R. J. Mathar_, Aug 23 2014

%Y Cf. A083521, A002383.

%K nonn

%O 1,1

%A _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 05 2003

%E More terms from _David Wasserman_, Nov 19 2004