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A195337
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Numbers whose home prime is a palindrome.
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1
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OFFSET
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1,1
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COMMENTS
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The home primes of 49 and 77 are not currently known. Other terms in this sequence include 101, 131, 151, 159, 181, 191, 219, 313, 373, 383, 532, 679, 727, 757, 787, 797, 919, 929,...
Numbers k such that A037274 is a palindrome. The palindromic primes (A002385) are a subsequence.
The non-palindromic numbers (or composite numbers) are 38, 39, 159, 219, 532, 679, ...
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LINKS
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EXAMPLE
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Home prime of 38 is 373.
Home prime of 39 is 313.
Home prime of 159 is 353.
Home prime of 219 is 373.
Home prime of 532 is 37573.
Home prime of 679 is 797.
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MAPLE
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filter:= proc(n)
local F, k, q;
F:= sort(map(t -> t[1]$t[2], ifactors(n)[2]));
F:= map(t -> op(ListTools:-Reverse(convert(t, base, 10))), F);
q:= add(F[-k]*10^(k-1), k=1..nops(F));
if isprime(q) then evalb(F = ListTools:-Reverse(F)) else procname(q) fi
end proc:
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CROSSREFS
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KEYWORD
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base,nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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