

A077798


Palindromic wing primes (a.k.a. nearrepdigit palindromic primes) of the general form r*(10^d  1)/9 + (mr)*10^floor(d/2) where d is the number of digits (an odd number > 1), r is the repeated digit, and m (different from r) is the middle digit.


48



101, 131, 151, 181, 191, 313, 353, 373, 383, 727, 757, 787, 797, 919, 929, 11311, 11411, 33533, 77377, 77477, 77977, 1114111, 1117111, 3331333, 3337333, 7772777, 7774777, 7778777, 111181111, 111191111, 777767777, 77777677777, 99999199999, 1111118111111
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OFFSET

1,1


COMMENTS

Prime versus probable prime status and proofs are given in the author's table.


REFERENCES

C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 199697, pp. 19.


LINKS

Jon E. Schoenfield, Table of n, a(n) for n = 1..124
P. De Geest, PWP Reference Table


PROG

(MAGMA) a:=[]; for d in [3..13 by 2] do for r in [1..9] do for m in [0..9] do if m ne r then t:=r*((10^d1) div 9) + (mr)*10^(d div 2); if IsPrime(t) then a[#a+1]:=t; end if; end if; end for; end for; end for; a; // Jon E. Schoenfield, Nov 04 2018


CROSSREFS

Cf. A077775A077797.
Sequence in context: A052086 A154270 A056730 * A089360 A056728 A085112
Adjacent sequences: A077795 A077796 A077797 * A077799 A077800 A077801


KEYWORD

nonn,base


AUTHOR

Patrick De Geest, Nov 16 2002


EXTENSIONS

Offset corrected by Arkadiusz Wesolowski, Sep 13 2011
Name edited and one more term added by Jon E. Schoenfield, Nov 03 2018


STATUS

approved



