A191715
Nonprime numbers of the form n*(n-1)^n - (n-1)*n^(n-1) + 1.
Original entry on oeis.org
1, 133, 54871, 1253659, 31438345, 863585785, 25867844011, 840625753991, 29488048443085, 1111334648458165, 44804977347486175, 1924820469011714611, 87800711122303545361, 4238935318038328143857, 11582179256389013503203871, 652184749150919163867112021
Offset: 1
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[ a: n in [2..40] | not IsPrime(a) where a is n*(n-1)^n-(n-1)*n^(n-1)+1 ]; // Vincenzo Librandi, Jun 13 2011
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Union[Select[Table[n(n-1)^n-(n-1)n^(n-1)+1,{n,30}],!PrimeQ[#]&]] (* Harvey P. Dale, Jun 19 2011 *)
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for(n=1,1e3,if(!ispseudoprime(k=n*(n-1)^n-(n-1)*n^(n-1)+1),print1(k", ")))
A110709
Nonprimes of the form n*(n-1)^n - 1.
Original entry on oeis.org
1, 323, 93749, 1959551, 46118407, 1207959551, 37661140520651, 1390911669927935, 55123269399790045, 2333521433367183359, 105094533691406249999, 5017514388048998039551, 13456471561751415850795007, 751799469150919163867112019
Offset: 1
a(1) = 1 = 2*1^2 - 1.
a(2) = 323 = 4*3^4 - 1.
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[a: n in [2..40] | not IsPrime(a) where a is n*(n-1)^n-1]; // Vincenzo Librandi, Jun 13 2011
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Select[Table[n (n - 1)^n - 1, {n, 2, 20}], ! PrimeQ[#] &] (* Vincenzo Librandi, Mar 22 2014 *)
A191409
Primes of the form n*(n-1)^n-(n-1)*n^(n-1)-1.
Original entry on oeis.org
5, 131, 54869, 863585783, 174960197237646244878763893842845824429634127969
Offset: 1
a(1)=5 (=3*2^3-2*3^2-1), a(2)=131 (=4*3^4-3*4^3-1), a(3)=54869 (=6*5^6-5*6^5-1), a(4)=863585783 (=9*8^9-8*9^8-1).
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Select[Table[n(n-1)^n-(n-1)n^(n-1)-1,{n,200}],PrimeQ] (* Harvey P. Dale, Jun 19 2011 *)
A191513
Numbers k such that k*(k-1)^k - 1 is prime.
Original entry on oeis.org
3, 5, 10, 11, 18, 127, 286, 560, 1025
Offset: 1
a(1)=3 because 3*2^3-1=23 is prime, a(2)=5 because 5*4^5-1=5119 is prime, a(3)=10 because 10*9^10-1=34867844009 is prime, a(4)=11 because 11*10^11-1=1099999999999 is prime.
A191717
Numbers k such that k*(k-1)^k - (k-1)*k^(k-1) + 1 is prime.
Original entry on oeis.org
3, 5, 18, 23, 78, 131, 177
Offset: 1
a(1)=3 because 3*2^3-2*3^2+1=7 is prime, a(2)=5 because 5*4^5-4*5^4+1=2621 is prime.
Showing 1-5 of 5 results.
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