

A088465


Primes whose leftmost decimal digit is 1 and whose other decimal digits are all 7's.


1




OFFSET

1,1


COMMENTS

In no element of this sequence can the number of 7's be congruent to 2 modulo 3.


LINKS

Table of n, a(n) for n=1..6.
Vladislav Avrutin, Prime pyramids
Makoto Kamada, Prime numbers of the form 177...77.
Index entries for primes involving repunits.


MATHEMATICA

Do[ a = 10^n + 7(10^n  1)/9; If[ PrimeQ[a], Print[a]], {n, 1, 53}] (* Robert G. Wilson v, Dec 05 2003 *)


CROSSREFS

Cf. A002275, A089147 (number of sevens).
Sequence in context: A055414 A156675 A276808 * A001905 A221322 A135505
Adjacent sequences: A088462 A088463 A088464 * A088466 A088467 A088468


KEYWORD

base,easy,nonn


AUTHOR

Sam Alexander, Nov 12 2003


STATUS

approved



