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A209620 Emirps that become their own reversals when rotated through 180 degrees (including on calculator display). 0
1021, 1151, 1181, 1201, 1511, 1811, 10151, 11551, 15101, 15511, 100511, 101281, 102181, 102551, 105211, 105251, 108881, 110051, 110221, 110281, 110881, 111211, 111821, 112111, 112181, 112501, 115001, 115021, 118081, 120121, 120511, 121021, 121151, 122011 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Such emirps have end digits 1 and use only digits 0, 1, 2, 5, 8, and the sequence naturally includes A155512, the emirps with only digits 0 and 1.
LINKS
EXAMPLE
1181 of this sequence, for instance, belongs to the emirp pair (1181, 1811), where each member is a 180-degree rotation of the other; similarly for the term 112501 of this sequence, that belongs to the emirp pair (105211, 112501) and which, displayed on a calculator and turned upside-down, becomes its own reversal.
MATHEMATICA
t1 = {0, 1, 2, 5, 8}; okQ[n_] := Module[{d = IntegerDigits[n], r}, r = Reverse[d]; r != d && Complement[d, t1] == {} && PrimeQ[FromDigits[r]]]; Select[Prime[Range[100000]], okQ] (* T. D. Noe, Apr 24 2012 *)
CROSSREFS
Cf. A006567.
Sequence in context: A356947 A214732 A088290 * A179032 A179033 A082059
KEYWORD
nonn,base
AUTHOR
Lekraj Beedassy, Mar 21 2012
STATUS
approved

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Last modified April 17 07:13 EDT 2024. Contains 371756 sequences. (Running on oeis4.)