OFFSET
2,1
COMMENTS
The corresponding index of the decimal digit 1 are 1, 0, 1, 2, 0, 0, 6, 0, 1, 2, 0, 2, 1, 0, 3, 0, 0, 5, 2,...(A241020).
LINKS
Michel Lagneau, Table of n, a(n) for n = 2..150
MAPLE
with(numtheory):nn:=80:T:=array(1..nn):
for n from 2 to nn do:
for i from 1 to n do:
T[i]:=7:
od:
ii:=0:
for j from 1 to n while(ii=0)do:
T[j]:=1:s:=sum('T[i]*10^(n-i)', 'i'=1..n):
if type(s, prime)=true
then
ii:=1: printf(`%d, `, s):
else
T[j]:=7:
fi:
od:
if ii=0
then
printf(`%d, `, 0):
else
fi:
od:
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Michel Lagneau, Apr 15 2014
STATUS
approved