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A158024
Primes p such that all the digits needed to write the consecutive Primes from 2 to p fill exactly a square (no holes, no overlaps).
2
2, 7, 29, 71, 101, 127, 191, 229, 317, 379, 499, 577, 733, 823, 10867, 11159, 12301, 12577, 13781, 14107, 15391, 15733, 17183, 17509, 19079, 19457, 21023, 21467, 23059, 23549, 25339, 25793, 27733, 28151, 30161, 30697, 32719, 33247, 35401
OFFSET
1,1
COMMENTS
The sides of the successive squares are given by A158025. Terms computed by Jean-Marc Falcoz.
LINKS
Eric Angelini, Digit Spiral
E. Angelini, Digit Spiral [Cached copy, with permission]
EXAMPLE
...2...23...2357
.......57...1113
............1719
............2329
The primes fitting exactly in the SE corner of the above squares are 2, 7, 29. There is no 3X3 square where this is possible.
MAPLE
X:= 0: p:= 1:
Res:= NULL: count:= 0:
while count < 100 do
p:= nextprime(p);
X:= X + ilog10(p) + 1;
if issqr(X) then Res:= Res, p; count:= count+1 fi
od:
Res; # Robert Israel, Jan 13 2020
CROSSREFS
Sequence in context: A285790 A083016 A062064 * A166940 A166939 A261182
KEYWORD
base,nonn
AUTHOR
Eric Angelini, Mar 11 2009
STATUS
approved