A101320 Numbers n such that 4n-1, 8n-1, 16n-1, 32n-1, 64n-1 and 128n-1 are primes.

15855, 31785, 267300, 280665, 399675, 561330, 946050, 990510, 1022220, 1082115, 1164735, 1283250, 1303875, 1309545, 1514880, 1669065, 1924410, 2850225, 3078675, 3092760, 3492270, 3536385, 3611205, 3920670, 4148970, 4454775

Offset

1,1

Links

Iain Fox, Table of n, a(n) for n = 1..1000

Example

4*15855-1, 8*15855-1, 16*15855-1, 32*15855-1, 64*15855-1 and 128*15855-1 are primes, so 15855 is a term.

Prog

(PARI) lista(nn) = for(n=15855, nn, if(ispseudoprime(4*n-1) && ispseudoprime(8*n-1) && ispseudoprime(16*n-1) && ispseudoprime(32*n-1) && ispseudoprime(64*n-1) && ispseudoprime(128*n-1), print1(n, ", "))) \\ Iain Fox, Nov 23 2017

Crossrefs

Cf. A002515, A101790, A101794, A101994.

Sequence in context: A356866 A184612 A277350 * A031811 A234318 A174596

Adjacent sequences: A101317 A101318 A101319 * A101321 A101322 A101323

Keyword

easy,nonn

Author

Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 23 2004

Status

approved