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A030670 Smallest prime whose decimal expansion begins (nontrivially) with the n-th prime. 5
23, 31, 53, 71, 113, 131, 173, 191, 233, 293, 311, 373, 419, 431, 479, 5323, 593, 613, 673, 719, 733, 797, 839, 8923, 971, 1013, 1031, 10711, 1091, 11311, 1277, 1319, 1373, 1399, 1493, 1511, 1571, 1637, 16729, 1733, 17911, 1811, 1913, 1931 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Add digits to p (starting with a nonzero digit) until another prime is reached.
LINKS
MAPLE
f:= proc(p) local d, x;
for d from 1 do
x:= nextprime(10^d*p+10^(d-1)-1);
if x < 10^d*(p+1) then return x fi
od
end proc:
map(f @ ithprime, [$1..100]); # Robert Israel, Aug 12 2018
MATHEMATICA
f[n_] := Block[{k = 1, p = Prime@ n}, While[a = 10^Floor[1 + Log10@ k] p + k; !PrimeQ@ a, k += 2]; a]; Array[f, 44]
CROSSREFS
See A064792 for another version. Note that A064792 <= a(n). Cf. A065112.
Sequence in context: A052230 A177981 A064792 * A030680 A330162 A006203
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified March 29 08:53 EDT 2024. Contains 371268 sequences. (Running on oeis4.)