A092609 Product of first n primes that end in 1.

11, 341, 13981, 852841, 60551711, 6115722811, 801159688241, 120975112924391, 21896495439314771, 4182230628909121261, 882450662699824586071, 212670609710657725243111, 53380323037375089036020861

Offset: 1

Author

Jorge Coveiro, Apr 11 2004

Keywords

• nonn
• easy

Examples

			a(1)= 11 = 11
a(2)= 11*31 = 341
a(3)= 11*31*41= 13981
a(4)= 11*31*41*61= 852841
		

Links

• Robert Israel, Table of n, a(n) for n = 1..286

Crossrefs

Cf. A030430.

Programs

Maple

Res:= NULL: p:= 1: count:= 0:
for n from 11 by 10 while count < 30 do
  if isprime(n) then count:= count+1; p:= p*n; Res:= Res,p fi
od:
Res; # Robert Israel, Sep 16 2018

Mathematica

Rest[FoldList[Times,1,Select[Prime[Range[70]],Mod[#,10]==1&]]] (* Harvey P. Dale, Jun 05 2013 *)

PARI

a(n) = {my(k=1, x=1); for (j=1, n, while(!isprime(10*k+1), k++); x *= (10*k+1); k++;); x;} \\ Michel Marcus, Nov 09 2020