

A158025


Sides of squares which are filled exactly (no holes, no overlaps) by the digits needed to write a subsequence of consecutive Primes starting with 2.


2



1, 2, 4, 6, 7, 8, 10, 11, 13, 14, 16, 17, 19, 20, 72, 73, 77, 78, 82, 83, 87, 88, 92, 93, 97, 98, 102, 103, 107, 108, 112, 113, 117, 118, 122, 123, 127, 128, 132, 133, 137, 138, 142, 143, 147, 148, 152, 153, 157, 158, 162, 163, 167, 168, 172, 173, 177, 178, 182, 183
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OFFSET

1,2


COMMENTS



LINKS



EXAMPLE

...2...23...2357
.......57...1113
............1719
............2329
The above squares, filled exactly by a subsequence of consecutive primes starting with 2 have sides 1, 2, 4. There is no side3 square with this property. The next properly filled square will have side 6.


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, sqrt(X); count:= count+1: fi
od:


CROSSREFS



KEYWORD

base,nonn


AUTHOR



STATUS

approved



