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A101320 Numbers n such that 4n-1, 8n-1, 16n-1, 32n-1, 64n-1 and 128n-1 are primes. 2
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 (list; graph; refs; listen; history; text; internal format)
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: A265669 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

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Last modified April 15 08:18 EDT 2021. Contains 342977 sequences. (Running on oeis4.)