A077203 a(1) = 2. Then the smallest n-digit prime starting with the last digit of the previous term.

2, 23, 307, 7001, 10007, 700001, 1000003, 30000001, 100000007, 7000000001, 10000000019, 900000000013, 3000000000013, 30000000000011, 100000000000031, 1000000000000037, 70000000000000003, 300000000000000011

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

Robert Israel, Table of n, a(n) for n = 1..995

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.

Maple

A[1]:= 2:
for n from 2 to 30 do A[n]:= nextprime((A[n-1] mod 10)*10^(n-1)) od:
seq(A[i], i=1..30); # Robert Israel, Jan 04 2023

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: A367677 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