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A115062
Prime nearest to 10^n. In case of a tie, choose the smaller.
2
2, 11, 101, 997, 10007, 100003, 1000003, 9999991, 100000007, 1000000007, 10000000019, 100000000003, 999999999989, 9999999999971, 99999999999973, 999999999999989, 10000000000000061, 99999999999999997, 1000000000000000003, 9999999999999999961
OFFSET
0,1
LINKS
FORMULA
a(n) = 10^n + A117190(n).
MAPLE
a:= n-> (t->((p, q)->`if`(q-t<t-p, q, p))(`if`(t=1, -1,
prevprime(t)), nextprime(t)))(10^n):
seq(a(n), n=0..25); # Alois P. Heinz, Aug 13 2014
MATHEMATICA
Table[Min[Nearest[{NextPrime[10^n], NextPrime[10^n, -1]}, 10^n]], {n, 0, 20}] (* Harvey P. Dale, Mar 14 2023 *)
PROG
(PARI) for(n=0, 20, a=10^n-precprime(10^n); b=nextprime(10^n)-10^n; if(a<=b && n!=0, print1(precprime(10^n), ", "), print1(nextprime(10^n), ", "))) \\ Felix Fröhlich, Aug 13 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Mar 01 2006
EXTENSIONS
More terms from Giovanni Resta and Rick L. Shepherd, Mar 01 2006
STATUS
approved