cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A340534 a(n) is the least product of n consecutive primes that is divisible by the sum of those primes, or 0 if there is no such product.

Original entry on oeis.org

2, 0, 30, 0, 15015, 0, 37182145, 9699690, 33426748355, 0, 3710369067405, 0, 304250263527210, 0, 37420578814667938361329, 0, 18598027670889965365580513, 0, 107254825578022430263302818471, 0, 44510752614879308559270669665465, 0, 267064515689275851355624017992790, 0, 116431182179248680450031658440253681535, 0
Offset: 1

Views

Author

J. M. Bergot and Robert Israel, Jan 10 2021

Keywords

Comments

a(27) > 10^225 if it is not 0.
If n is even, a(n) is either A002110(n) or 0.
a(n) = A002110(n) for n in A051838.

Examples

			a(5) = 15015 = 3*5*7*11*13 is the product of 5 consecutive primes and is divisible by 3+5+7+11+13 = 39.
		

Crossrefs

Programs

  • Maple
    f:= proc(n) local L,i,p;
       L:= [seq(ithprime(i),i=1..n)]:
       p:= convert(L,`*`);
       if n::even then
         if p mod convert(L,`+`) = 0 then return p else return 0 fi
       else
         do
           p:= convert(L,`*`);
           if p mod convert(L,`+`) = 0 then return p fi;
           if p > 10^225 then return FAIL fi;
           L:= [op(L[2..-1]),nextprime(L[-1])];
         od
       fi;
    end proc:
    map(f, [$1..26]);