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A330160
Positions of 2 in A309059.
0
3, 7, 10, 15, 22, 45, 227, 700, 5170, 11147, 11869, 16005, 19227
OFFSET
1,1
FORMULA
A309059(a(n))=2.
EXAMPLE
a(3)=10 is in the sequence because A309059(10)=2.
MAPLE
x:= 1: Res:= NULL:
for i from 2 to 10000 do
if isprime(x) then Res:= Res, i; x:= 10*x+2;
else x:= 10*x+1
fi
od:
Res;
CROSSREFS
Cf. A309059.
Sequence in context: A353654 A143101 A307612 * A373186 A281642 A353427
KEYWORD
nonn,more
AUTHOR
Robert Israel, Dec 03 2019
EXTENSIONS
a(10)-a(11) from Robert Israel, Dec 17 2019
a(12)-a(13) from Michael S. Branicky, Jun 24 2024
STATUS
approved