

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
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OFFSET

1,1


COMMENTS

The sides of the successive squares are given by A158025. Terms computed by JeanMarc Falcoz.


LINKS

Robert Israel, Table of n, a(n) for n = 1..3000
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
Adjacent sequences: A158021 A158022 A158023 * A158025 A158026 A158027


KEYWORD

base,nonn


AUTHOR

Eric Angelini, Mar 11 2009


STATUS

approved



