A088265 -id:A088265 - cp's OEIS frontend

A088266 Smallest number that yields a prime when concatenated with A088265(k) for all k <= n.

2, 3, 3, 189, 210, 31296, 105441, 105441, 46814571, 665216481, 111581348556, 1199096907504

Offset: 1

Amarnath Murthy, Sep 28 2003

a(n) == 0 (mod 3) for n > 1.
a(n) <> 4 (mod 7) and a(n) <> 9 (mod 11) for n > 2 (where <> means "not equal"). - M. F. Hasler, Oct 15 2012
Terms a(13) onward do not exist as at least one of the corresponding concatenations is always divisible by 7. - Max Alekseyev, Oct 14 2012

			a(1) = 2 since 211 is prime.
a(4) = 189 since 18911, 18913, 18917 and 18919 are all prime.

Cf. A088265, A088267.

A088266(n)=for(t=1,9e9,for(k=1,n,isprime(t*10^((k+7)\4)+A088265(k))||next(2));return(t))  \\ Only useful for n<9. - M. F. Hasler, Oct 15 2012

More terms from David Wasserman, Jul 27 2005
a(10..12) from Don Reble, Oct 15 2012
a(10..12) confirmed by D. S. McNeil, Oct 16 2012

A088267 Smallest number that on prefixing with the n-th term of A088265 yields prime.

Original entry on oeis.org

2, 1, 3, 4, 5, 1, 5, 1, 2, 1, 6, 9, 18, 9, 5, 4, 2, 7, 3, 1, 6, 3, 11, 9, 20, 6, 32, 16, 11, 13, 11, 1, 6, 15, 6, 21, 18, 1, 5, 13, 14, 1, 6, 18, 15, 9, 12, 3, 50, 19, 56, 12, 9, 3, 5, 66, 27, 1, 8, 24, 11, 9, 11, 13, 24, 79, 3, 43, 26, 19, 11, 4, 39, 3, 45, 9, 11, 6, 6, 15, 2, 1, 41, 18, 5, 19

Offset: 0

Amarnath Murthy, Sep 28 2003

			a(13) = 18 as A088265(13) = 10001 and 1810001 is a prime while 110001, 210001 to 1710001 are all composite.

Cf. A088265, A088267.

More terms from David Wasserman, Jul 28 2005

cp's OEIS Frontend

A088266 Smallest number that yields a prime when concatenated with A088265(k) for all k <= n.

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