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A228134
Primes expressible as concatenation of reversals of two consecutive squares, in order of their occurrence (ignoring leading zeros).
1
181, 121441, 961691, 676927, 1489, 94816391, 63139423, 631273, 63885209, 52096129, 10891, 4040190601, 6992152231, 4293116141, 16141441, 44114641, 96116171, 9231348613, 4861314023, 4213398433, 5224369543, 12753163, 9821742817, 14877487, 16912769, 1276944379, 923401679401
OFFSET
1,1
LINKS
EXAMPLE
a(3)= 961691. It is a prime and is concatenation of 961 and 691 which are the reversals of 13^2 and 14^2, two consecutive squares.
MAPLE
with(StringTools):KD:= proc() local a, b, c, d; a:= parse(Reverse(convert(((n)^2), string))); b:=parse(Reverse(convert(((n+1)^2), string))); d:=parse(cat(a, b)) ; if isprime(d) then RETURN (d) : fi; end:seq(KD(), n=1..500);
MATHEMATICA
Select[FromDigits[Flatten[IntegerDigits/@#]]&/@Partition[IntegerReverse/@ (Range[ 400]^2), 2, 1], PrimeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 21 2020 *)
CROSSREFS
Sequence in context: A189778 A322904 A107075 * A066626 A185824 A324271
KEYWORD
nonn,base,less
AUTHOR
K. D. Bajpai, Aug 12 2013
STATUS
approved