A242176
Numbers k such that k*6^k + 1 is prime.
Original entry on oeis.org
1, 2, 91, 185, 387, 488, 747, 800, 9901, 10115, 12043, 13118, 30981, 51496
Offset: 1
Cf. numbers n such that n*k^n + 1 is prime:
A005849 (k=2),
A006552 (k=3),
A007646 (k=4), this sequence (k=6),
A242177 (k=7),
A242178 (k=8),
A007647 (k=10),
A242196 (k=12),
A242197 (k=14),
A242198 (k=15),
A242199 (k=16),
A007648 (k=18).
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[n: n in [0..1500] | IsPrime(n*6^n+1)];
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Select[Range[1500], PrimeQ[# 6^# + 1] &]
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is(n)=ispseudoprime(n*6^n+1) \\ Charles R Greathouse IV, Feb 17 2017
A242271
Numbers n such that n*8^n+1 is semiprime.
Original entry on oeis.org
1, 2, 3, 9, 24, 32, 35, 51, 75, 234, 243, 392, 417, 472
Offset: 1
Cf. similar sequences listed in
A242203.
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IsSemiprime:=func; [n: n in [1..80] | IsSemiprime(s) where s is n*8^n+1];
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Select[Range[80], PrimeOmega[# 8^# + 1] == 2 &]
A265013
Numbers n such that n*9^n + 1 is prime.
Original entry on oeis.org
2, 12382, 27608, 31330, 117852
Offset: 1
Cf.
A005849,
A006552,
A007646,
A242176,
A242177,
A242178,
A007647,
A242196,
A242197,
A242198,
A242199,
A007648.
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[n: n in [0..100000] | IsPrime(n*9^n+1)];
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Select[Range[100000], PrimeQ[# 9^# + 1] &]
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for(n=1,100000, if(isprime(n*9^n+1), print1(n,", ")))
A338412
Numbers k such that k * 20^k + 1 is prime.
Original entry on oeis.org
3, 6207, 8076, 22356, 151456
Offset: 1
Numbers k such that k * b^k + 1 is prime:
A006093 (b=1),
A005849 (b=2),
A006552 (b=3),
A007646 (b=4),
A242176 (b=6),
A242177 (b=7),
A242178 (b=8),
A265013 (b=9),
A007647(b=10),
A242196(b=12),
A242197 (b=14),
A242198 (b=15),
A242199 (b=16),
A007648 (b=18), this sequence (b=20).
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[n: n in [1..10000] |IsPrime(n*20^n+1)]
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Select[Range[1, 10000], PrimeQ[n*20^n+1] &]
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for(n=1, 10000, if(isprime(n*20^n+1), print1(n, ", ")))
Showing 1-4 of 4 results.
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