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A030481
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Squares of primes, with property that all even digits occur together and all odd digits occur together.
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1
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4, 9, 25, 49, 289, 841, 2209, 2809, 4489, 6241, 6889, 22201, 22801, 24649, 66049, 80089, 208849, 426409, 466489, 822649, 2042041, 2468041, 2866249, 2886601, 4068289, 6046681, 6086089, 6466849, 6806881, 6848689, 8082649, 8288641, 8462281, 8826841, 22648081, 26020201, 26822041, 28440889, 44262409
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OFFSET
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1,1
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COMMENTS
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Since the 10's digit of any odd square is even, all digits except the last must be even. - Robert Israel, Jan 04 2024
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LINKS
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MAPLE
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filter:= proc(n) local L;
convert(convert(floor(n/10), base, 10), set) mod 2 = {0}
end proc:
[4, 9, op(select(filter, [seq(ithprime(i)^2, i=3..20000)]))]; # Robert Israel, Jan 04 2024
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CROSSREFS
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Includes (2*10^(2k) + 2*10^k + 1)^2 for k in A296444.
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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