A240234 -id:A240234 - cp's OEIS frontend

A327661 Least number k > n - 2 such that k*n^k - 1 is prime.

3, 2, 2, 3, 8, 19, 18, 7, 10, 11, 252, 43, 563528, 98, 14, 167, 18, 28, 410, 44, 200, 140, 29028, 124, 68, 79, 2420, 47, 26850, 63, 2454, 140, 42, 164, 38, 62, 740, 67, 448, 51, 84, 135, 404882, 43, 84, 140, 140, 115, 710, 2390, 46640, 261, 60, 72, 2064, 414

Offset: 1

Jeppe Stig Nielsen, Sep 21 2019

Different version of A240235. Some authors, like Caldwell (link), require that k + 2 > n before they use the term generalized Woodall for a prime of form k*n^k - 1.

			To find a(11), consider numbers k*11^k - 1 where k > 9. The first time it is prime, is for k = 252, so a(11) = 252.

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..144
Chris K. Caldwell, The Top Twenty: Generalized Woodall.

Cf. A240235, A327660, A240234.

for(b=1,+oo,for(k=b-1,+oo,if(ispseudoprime(k*b^k-1),print1(k,", ");next(2))))

A327660 Least number k > n - 2 such that k*n^k + 1 is prime.

Original entry on oeis.org

1, 1, 2, 3, 1242, 91, 34, 17, 12382, 9, 10, 247

Offset: 1

Jeppe Stig Nielsen, Sep 21 2019

Different version of A240234. Some authors, like Caldwell (link), require that k + 2 > n before they use the term generalized Cullen for a prime of form k*n^k + 1.

			To find a(9), consider numbers k*9^k + 1 where k > 7. The first time it is prime, is for k = 12382, so a(9) = 12382.

Chris K. Caldwell, The Top Twenty: Generalized Cullen.

Cf. A240234, A327661, A240235.

for(b=1,+oo,for(k=b-1,+oo,if(ispseudoprime(k*b^k+1),print1(k,", ");next(2))))

cp's OEIS Frontend

A327661 Least number k > n - 2 such that k*n^k - 1 is prime.

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