A003618 -id:A003618 - cp's OEIS frontend

A099667 a(n) is the largest prime before A002281(n); repdigits repeating 7.

5, 73, 773, 7759, 77773, 777769, 7777769, 77777761, 777777773, 7777777741, 77777777767, 777777777773, 7777777777771, 77777777777753, 777777777777773, 7777777777777753, 77777777777777747, 777777777777777743

Offset: 1

Labos Elemer, Nov 17 2004

			n=2: 73 is before 77.

Michael De Vlieger, Table of n, a(n) for n = 1..1000

Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

Table[NextPrime[7 (10^n - 1)/9, -1], {n, 35}]
(* Second program: *)
Rest[NextPrime[#,-1]&/@LinearRecurrence[{11,-10},{0,7},25]] (* Harvey P. Dale, May 24 2015 *)

Name changed by David A. Corneth, Sep 01 2017

A115062 Prime nearest to 10^n. In case of a tie, choose the smaller.

Original entry on oeis.org

2, 11, 101, 997, 10007, 100003, 1000003, 9999991, 100000007, 1000000007, 10000000019, 100000000003, 999999999989, 9999999999971, 99999999999973, 999999999999989, 10000000000000061, 99999999999999997, 1000000000000000003, 9999999999999999961

Offset: 0

Lekraj Beedassy, Mar 01 2006

nonn

Alois P. Heinz, Table of n, a(n) for n = 0..300

Cf. A003617, A003618, A117190.

a:= n-> (t->((p, q)->`if`(q-tAlois P. Heinz, Aug 13 2014

Table[Min[Nearest[{NextPrime[10^n],NextPrime[10^n,-1]},10^n]],{n,0,20}] (* Harvey P. Dale, Mar 14 2023 *)

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

a(n) = 10^n + A117190(n).

More terms from Giovanni Resta and Rick L. Shepherd, Mar 01 2006

A157035 Largest prime with 2^n digits.

Original entry on oeis.org

7, 97, 9973, 99999989, 9999999999999937, 99999999999999999999999999999979, 9999999999999999999999999999999999999999999999999999999999999949

Offset: 0

Lekraj Beedassy, Feb 22 2009

Cf. A157036, A003618, A157033, A157034.

NextPrime[10^2^Range[0,6],-1] (* Harvey P. Dale, Dec 28 2023 *)

A073862 Difference between the largest and the smallest n-digit prime.

Original entry on oeis.org

5, 86, 896, 8964, 89984, 899980, 8999988, 89999970, 899999930, 8999999960, 89999999958, 899999999986, 8999999999932, 89999999999936, 899999999999958, 8999999999999900, 89999999999999936, 899999999999999986, 8999999999999999958, 89999999999999999938

Offset: 1

Amarnath Murthy, Aug 15 2002

			a(3) = 997 - 101 = 896.
a(1) = 5 because 7-2 = 5.

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Cf. A003617, A003618.

seq(prevprime(10^n)-nextprime(10^(n-1)), n=1..21); # Emeric Deutsch, Mar 28 2005

Table[NextPrime[10^(n+1),-1]-NextPrime[10^n],{n,0,18}] (* Harvey P. Dale, May 04 2016 *)

a(n) = A003618(n) - A003617(n).

More terms from Emeric Deutsch, Mar 28 2005

A099658 a(n) is the smallest prime greater than 4(10^n - 1)/9.

Original entry on oeis.org

2, 5, 47, 449, 4447, 44449, 444449, 4444469, 44444453, 444444457, 4444444447, 44444444497, 444444444461, 4444444444493, 44444444444459, 444444444444461, 4444444444444463, 44444444444444461, 444444444444444469, 4444444444444444537, 44444444444444444447

Offset: 0

Labos Elemer, Nov 17 2004

a(n) = smallest prime > A002278(n).

			n=4: 44 is followed by 47.

Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

Table[NextPrime[4*(10^n-1)/9], {n, 0, 35}]

Checked by N. J. A. Sloane, Jan 27 2007

Mathematica program edited by Harvey P. Dale, Jul 16 2024

A099659 a(n) is the least prime following A002279(n) repdigits.

Original entry on oeis.org

7, 59, 557, 5557, 55579, 555557, 5555567, 55555559, 555555587, 5555555557, 55555555619, 555555555559, 5555555555593, 55555555555573, 555555555555557, 5555555555555573, 55555555555555639, 555555555555555559, 5555555555555555621, 55555555555555555567, 555555555555555555619

Offset: 1

Labos Elemer, Nov 17 2004

			n=2: 55 is followed by 59.

Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

Table[NextPrime[5*(10^n-1)/9], {n, 1, 35}]

Offset corrected by Georg Fischer, Mar 12 2024

A099660 a(n) is the least prime following A002280[n] repdigits.

Original entry on oeis.org

2, 7, 67, 673, 6673, 66683, 666667, 6666679, 66666667, 666666667, 6666666757, 66666666667, 666666666671, 6666666666683, 66666666666737, 666666666666719, 6666666666666719, 66666666666666713, 666666666666666773

Offset: 0

Labos Elemer, Nov 17 2004

			n=6: 66 is followed by 67.

Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

Table[NextPrime[6*(10^n-1)/9], {n, 0, 35}]
NextPrime/@Table[FromDigits[PadRight[{},n,6]],{n,0,20}] (* Harvey P. Dale, Feb 25 2015 *)

First Mathematica program corrected by Harvey P. Dale, Feb 25 2015

A099662 a(n) is the least prime following A002282(n) repdigits.

Original entry on oeis.org

2, 11, 89, 907, 8893, 88897, 888917, 8888927, 88888901, 888888901, 8888888891, 88888888901, 888888888919, 8888888888921, 88888888888889, 888888888888907, 8888888888888927, 88888888888888889, 888888888888888947

Offset: 0

Labos Elemer, Nov 17 2004

			n=8: 88 is followed by 89.

Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

Table[NextPrime[8*(10^n-1)/9], {n, 0, 35}]

A099664 a(n) is the largest prime before A002278(n).

Original entry on oeis.org

3, 43, 443, 4441, 44417, 444443, 4444409, 44444399, 444444443, 4444444429, 44444444441, 444444444443, 4444444444439, 44444444444353, 444444444444421, 4444444444444423, 44444444444444411, 444444444444444419

Offset: 1

Labos Elemer, Nov 17 2004

			n=2: 43 is before 44.

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A003618, A003617, A096497, A096498, A068104, A002275-A002283, A099656-A099668.

Mathematica
```
<Harvey P. Dale, Feb 25 2013 *)
```

A101592 Smallest and largest of the n-digit primes.

Original entry on oeis.org

2, 7, 11, 97, 101, 997, 1009, 9973, 10007, 99991, 100003, 999983, 1000003, 9999991, 10000019, 99999989, 100000007, 999999937, 1000000007, 9999999967, 10000000019, 99999999977, 100000000003, 999999999989, 1000000000039, 9999999999971, 10000000000037

Offset: 1

Parthasarathy Nambi, Jan 26 2005

			2 is the smallest 1-digit prime and 7 is the largest 1-digit prime.
100003 is the smallest 6-digit prime and 999983 is the largest 6-digit prime.

Harvey P. Dale, Table of n, a(n) for n = 1..1000
Chris K. Caldwell List of small primes.

Cf. A003617, A003618

Table[{NextPrime[10^n],NextPrime[10^(n+1),-1]},{n,0,15}]//Flatten (* Harvey P. Dale, Jun 04 2019 *)

cp's OEIS Frontend

A099667 a(n) is the largest prime before A002281(n); repdigits repeating 7.

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A115062 Prime nearest to 10^n. In case of a tie, choose the smaller.

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A157035 Largest prime with 2^n digits.

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A073862 Difference between the largest and the smallest n-digit prime.

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A099658 a(n) is the smallest prime greater than 4(10^n - 1)/9.

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A099659 a(n) is the least prime following A002279(n) repdigits.

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A099660 a(n) is the least prime following A002280[n] repdigits.

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A099662 a(n) is the least prime following A002282(n) repdigits.

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A099664 a(n) is the largest prime before A002278(n).

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