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A108835 Primes such that the outer 2 digits are n and n-1 and all inner digits are 7, where 0 < n < 9. 0
271, 877, 2777771, 8777777777, 8777777777777777, 877777777777777777777777777777777, 2777777777777777777777777777777771, 877777777777777777777777777777777777777, 877777777777777777777777777777777777777777777777777777777777777777 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..9.

PROG

(PARI) n10np1(n, d) = { local(x, y, k); for(x=1, n, for(k=1, 8, y=10^(x+1)*k+floor(10^x*d/9)*10+k-1; if(isprime(y), print1(y", ")) ) ) }

CROSSREFS

Sequence in context: A245969 A157485 A038655 * A185668 A296038 A287232

Adjacent sequences:  A108832 A108833 A108834 * A108836 A108837 A108838

KEYWORD

easy,nonn,base

AUTHOR

Cino Hilliard, Jul 11 2005

EXTENSIONS

One more term (a(9)) from Harvey P. Dale, Jul 23 2012

STATUS

approved

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Last modified April 10 21:41 EDT 2021. Contains 342856 sequences. (Running on oeis4.)