A113630 -id:A113630 - cp's OEIS frontend

A249951 Numbers n such that A113630(n) is prime.

3, 5, 8, 23, 42, 62, 63, 75, 90, 98, 177, 192, 207, 213, 222, 228, 233, 263, 288, 297, 317, 320, 402, 453, 455, 528, 570, 602, 620, 650, 672, 752, 780, 797, 810, 863, 867, 870, 875, 912, 932, 935, 978, 1010, 1043, 1065, 1067, 1070, 1110, 1125, 1133, 1142, 1190

Offset: 1

Chai Wah Wu, Nov 09 2014

nonn

A113630(n) = 1 + 2*n + 3*n^2 + 4*n^3 + 5*n^4 + 6*n^5 + 7*n^6 + 8*n^7 + 9*n^8.

			See example section of A113630.

Chai Wah Wu, Table of n, a(n) for n = 1..2434

Cf. A113630.

Cf. A010051.

a249951 n = a249951_list !! (n-1)
a249951_list = filter ((== 1) . a010051'' . a113630) [1..]
-- Reinhard Zumkeller, Nov 22 2014

[n: n in [0..1500] | IsPrime(1+2*n+3*n^2+4*n^3+ 5*n^4+6*n^5+7*n^6+8*n^7+9*n^8)]; // Vincenzo Librandi, Nov 09 2014

for(n=1,5000,s=sum(i=1,9,i*n^(i-1));if(ispseudoprime(s),print1(n,", "))) \\ Derek Orr, Nov 09 2014

from sympy import isprime
A249951_list, m = [], [362880, -1229760, 1607760, -1011480, 309816, -40752, 1584, -4, 1]
for n in range(1,10**5+1):
    for i in range(8):
        m[i+1]+= m[i]
    if isprime(m[-1]):
        A249951_list.append(n)

A096209 Primes of the form 10 followed by 9's only.

Original entry on oeis.org

109, 10999999999, 1099999999999, 1099999999999999999, 109999999999999999999999, 1099999999999999999999999999999, 10999999999999999999999999999999999999

Offset: 1

Cino Hilliard, Jul 28 2004

Or, primes of the form 10^k + 10^(k-1) - 1.

Number of 9's in a(n) is given by A111391(n). - Daniel Starodubtsev, Jan 06 2020

Cf. A111391, A113628, A113629, A113630.

Primes in A198700.

t = {}; Do[m = n; p = 10^(n + 1) + (10^n - 1); If[PrimeQ[p], AppendTo[t, p]], {n, 165}]; t (* Robert G. Wilson v *)

f(n) = for(x=1,n,y=10^x+10^(x-1)-1;if(ispseudoprime(y),print1(y", ")))

a(n) = 11*10^A111391(n) - 1 = A198700(A111391(n)). - Elmo R. Oliveira, Jun 14 2025

Entry revised by N. J. A. Sloane, Apr 01 2006

A113629 Primes of the form 10 followed by a string of 3's.

Original entry on oeis.org

103, 1033, 10333, 103333, 10333333, 103333333, 1033333333, 10333333333333, 10333333333333333333, 10333333333333333333333333333333, 10333333333333333333333333333333333333333333333333333333333333333333333333333

Offset: 1

Amarnath Murthy, Nov 10 2005

Cf. A113628, A113630, A096209.

More terms from Jim Nastos, Nov 15 2005

cp's OEIS Frontend

A249951 Numbers n such that A113630(n) is prime.

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A096209 Primes of the form 10 followed by 9's only.

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Programs

Mathematica

PARI

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Extensions

A113629 Primes of the form 10 followed by a string of 3's.

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Author

Keywords

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Extensions