A187559 Primes arising in A187234.

2, 3, 5, 7, 2, 3, 5, 7, 2, 3, 5, 7, 3, 5, 7, 11, 13, 17, 19, 2, 5, 11, 17, 23, 29, 3, 7, 11, 19, 23, 31, 19, 29, 5, 11, 17, 23, 29, 41, 47, 53, 59, 13, 41, 7, 23, 31, 47, 71, 79, 17, 53, 71, 89, 19, 29, 59, 79, 89, 2, 2, 5, 11, 17, 23, 29, 11, 31, 41, 17, 31, 59, 73, 23, 41, 59, 29, 73, 3, 3, 7, 11, 19, 23, 31, 11, 31, 41, 19, 47, 61, 23

Offset

1,1

Links

Table of n, a(n) for n=1..92.

Example

a(22) = 11 because A187234(22) = 123, and 1*2 + 1*3 + 2*3 = 11 is prime.

Maple

with(numtheory):T:=array(1..10):k:=1:for n from 1 to 1000 do:l:=length(n):n0:=n:for
  m from 1 to l do:q:=n0:u:=irem(q, 10):v:=iquo(q, 10):n0:=v :T[m]:=u:od: s:=0:
  for i from 1 to l-1 do: for j from i+1 to l do: s:=s+T[i]*T[j]:od: od:if type(s, prime)
  = true then printf(`%d, `, s):else fi:od:

Crossrefs

Cf. A187234.

Sequence in context: A229875 A230199 A275542 * A104212 A139751 A076779

Adjacent sequences: A187556 A187557 A187558 * A187560 A187561 A187562

Keyword

nonn,base,easy

Author

Michel Lagneau, Mar 11 2011

Status

approved