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A077203 a(1) = 2. Then the smallest n-digit prime starting with the last digit of the previous term. 0
2, 23, 307, 7001, 10007, 700001, 1000003, 30000001, 100000007, 7000000001, 10000000019, 900000000013, 3000000000013, 30000000000011, 100000000000031, 1000000000000037, 70000000000000003, 300000000000000011 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Before correction the sequence began as follows: 2, 23, 311, 1009, 90001, 100003, 3000017. However the third term is incorrect since the smallest 3-digit prime with most significant digit 3 is 307 not 311. - Alexis Olson (AlexisOlson(AT)gmail.com), Nov 14 2008

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

a(5) = 90001 has (LSD) Least Significant Digit as 1 and a(6) = 100003, the smallest 6 digit prime with the most significant digit as 1.

MATHEMATICA

For[i = 1; v = 2; s = {}, i <= 500, i++, LSD = IntegerDigits[v][[-1]]; For[n = LSD*10^i, n <= 2*LSD*10\^i, n++, If[PrimeQ[n], v = n; s = Union[s, {n}]; Break[]]]]; s (* Alexis Olson, Nov 14 2008 *)

NestList[NextPrime[Mod[#, 10]10^IntegerLength[#]]&, 2, 20]  (* Harvey P. Dale, Apr 03 2011 *)

CROSSREFS

Sequence in context: A126040 A294161 A088641 * A173935 A216549 A091693

Adjacent sequences:  A077200 A077201 A077202 * A077204 A077205 A077206

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Nov 02 2002

EXTENSIONS

Corrected and extended by Alexis Olson (AlexisOlson(AT)gmail.com), Nov 14 2008

STATUS

approved

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Last modified October 15 10:46 EDT 2019. Contains 328026 sequences. (Running on oeis4.)