A249951 - OEIS

%I #14 Sep 08 2022 08:46:10

%S 3,5,8,23,42,62,63,75,90,98,177,192,207,213,222,228,233,263,288,297,

%T 317,320,402,453,455,528,570,602,620,650,672,752,780,797,810,863,867,

%U 870,875,912,932,935,978,1010,1043,1065,1067,1070,1110,1125,1133,1142,1190

%N Numbers n such that A113630(n) is prime.

%C 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.

%H Chai Wah Wu, <a href="/A249951/b249951.txt">Table of n, a(n) for n = 1..2434</a>

%e See example section of A113630.

%o (Python)

%o from sympy import isprime

%o A249951_list, m = [], [362880, -1229760, 1607760, -1011480, 309816, -40752, 1584, -4, 1]

%o for n in range(1,10**5+1):

%o ....for i in range(8):

%o ........m[i+1]+= m[i]

%o ....if isprime(m[-1]):

%o ........A249951_list.append(n)

%o (PARI) for(n=1,5000,s=sum(i=1,9,i*n^(i-1));if(ispseudoprime(s),print1(n,", "))) \\ _Derek Orr_, Nov 09 2014

%o (Magma) [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

%o (Haskell)

%o a249951 n = a249951_list !! (n-1)

%o a249951_list = filter ((== 1) . a010051'' . a113630) [1..]

%o -- _Reinhard Zumkeller_, Nov 22 2014

%Y Cf. A113630.

%Y Cf. A010051.

%K nonn

%O 1,1

%A _Chai Wah Wu_, Nov 09 2014