

A077795


Numbers k such that (10^k  1)/9 + 8*10^floor(k/2) is a palindromic wing prime (a.k.a. nearrepdigit palindromic prime).


2




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

Table of n, a(n) for n=1..7.
Patrick De Geest, World!Of Numbers, Palindromic Wing Primes (PWP's)
Makoto Kamada, Prime numbers of the form 11...11911...11
Index entries for primes involving repunits.


FORMULA

a(n) = 2*A107649(n) + 1.


EXAMPLE

9 is a term because (10^9  1)/9 + 8*10^4 = 111191111.


CROSSREFS

Cf. A004023, A077775A077798, A107123A107127, A107648, A107649, A115073, A183174A183187.
Sequence in context: A018477 A226931 A013341 * A038496 A175596 A261397
Adjacent sequences: A077792 A077793 A077794 * A077796 A077797 A077798


KEYWORD

more,nonn,base


AUTHOR

Patrick De Geest, Nov 16 2002


EXTENSIONS

Name corrected by Jon E. Schoenfield, Oct 30 2018


STATUS

approved



