A073186 First n-digit prime in the concatenation of the even integers forbidding leading zeros.

2, 41, 101, 8101, 30323, 141161, 2468101, 42628303, 246810121, 8101214161, 68101214161, 890929496981, 1081101121141, 68890929496981, 202224262830323, 6416616817017217, 58606264666870727, 618202224262830323

Offset

1,1

Comments

Leading zeros are forbidden (cf. A073468).

Links

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

Example

a(6)=141161 because first 6-digit prime in 246810121416182022242628303234... is 141161 (omitting initial zeros, otherwise 6 successive integers which give first "6-digital" prime are "001021" )

Mathematica

p200=Flatten[IntegerDigits[2*Range[200]]]; Do[pn=Partition[p200, n, 1]; ln=Length[pn]; tab=Table[Sum[10^(n-k)*pn[[i, k]], {k, n}], {i, ln}]; tas=Select[tab, PrimeQ]; Print[{n, tas[[1]], tas[[2]], tas[[3]]}], {n, 20}]

Crossrefs

Sequence in context: A377718 A285792 A073468 * A103335 A047936 A007533

Adjacent sequences: A073183 A073184 A073185 * A073187 A073188 A073189

Keyword

nonn,base

Author

Zak Seidov, Aug 22 2002

Extensions

Corrected and extended by Sascha Kurz, Feb 02 2003

Name modified by Sean A. Irvine, Jan 31 2025

Status

approved