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A101792 Primes of the form 8*k-1 such that 4*k-1 and 16*k-1 are also primes. 6
23, 359, 719, 1439, 2039, 2063, 2903, 3023, 3623, 3863, 4919, 5399, 5639, 6983, 7079, 7823, 10799, 12263, 14159, 14303, 21383, 22343, 22943, 24239, 25799, 25919, 33623, 34319, 36383, 38639, 39983, 40823, 42023, 42359, 44543, 46199, 47639, 48479, 49103, 54959 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) = 8*A101790(n) - 1 = 2*A101791(n) + 1. - Amiram Eldar, May 13 2024
EXAMPLE
4*3 - 1 = 11, 8*3 - 1 = 23 and 16*3 - 1 = 47 are primes, so 23 is a term.
MATHEMATICA
8 * Select[Range[10^4], And @@ PrimeQ[2^Range[2, 4]*# - 1] &] - 1 (* Amiram Eldar, May 13 2024 *)
PROG
(PARI) for(k=1, 7000, if(isprime(8*k-1)&&isprime(4*k-1)&&isprime(16*k-1), print1(8*k-1, ", "))) \\ Hugo Pfoertner, Sep 07 2021
CROSSREFS
Subsequence of A007522.
Subsequences: A101796, A101996.
Sequence in context: A118115 A020572 A021884 * A020346 A025964 A180361
KEYWORD
easy,nonn
AUTHOR
Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004
STATUS
approved

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Last modified June 23 20:17 EDT 2024. Contains 373653 sequences. (Running on oeis4.)