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A128946 Numbers n such that the largest prime < 10^n is a twin prime member. 0
1, 5, 14, 406, 1118, 4934 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A003618(a(n)) is in A001097 (Twin primes).

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

For n=1, 10^1 = 10. 7, the greatest prime < 10, is a member of the twin prime pair 5,7.

PROG

(PARI) g(n)=for(x=1, n, y=precprime(10^x); if(ispseudoprime(y-2), print1(x", ")))

CROSSREFS

Sequence in context: A317691 A067857 A027832 * A156219 A000331 A306155

Adjacent sequences:  A128943 A128944 A128945 * A128947 A128948 A128949

KEYWORD

hard,more,nonn

AUTHOR

Cino Hilliard, Apr 28 2007

EXTENSIONS

Edited by Ray Chandler, May 12 2007

a(5), a(6) from Donovan Johnson, Feb 21 2008

STATUS

approved

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Last modified September 17 06:16 EDT 2021. Contains 347478 sequences. (Running on oeis4.)