

A077778


Numbers k such that (10^k  1)  7*10^floor(k/2) is a palindromic wing prime (a.k.a. nearrepdigit palindromic prime).


2



3, 17, 19, 705, 1061, 1395, 2631, 3837, 5749, 11753, 13537, 125877, 269479
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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



FORMULA



EXAMPLE

17 is a term because (10^17  1)  7*10^8 = 99999999299999999.


MATHEMATICA

Do[ If[ PrimeQ[10^n  7*10^Floor[n/2]  1], Print[n]], {n, 3, 14600, 2}] (* Robert G. Wilson v, Dec 16 2005 *)


CROSSREFS



KEYWORD

more,nonn,base


AUTHOR



EXTENSIONS



STATUS

approved



