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A248346 Primes of the form 2^x - y^2. 2
2, 3, 7, 23, 31, 47, 71, 79, 103, 127, 151, 199, 223, 271, 367, 431, 463, 487, 503, 727, 751, 823, 967, 1087, 1303, 1319, 1423, 1439, 1607, 1759, 1823, 1879, 1951, 1999, 2039, 2143, 3527, 3967 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes in A051213.

LINKS

Table of n, a(n) for n=1..38.

EXAMPLE

7 is in this sequence because 7 = 2^3 - 1^2 = 2^4 - 3^2 = 2^5 - 5^2 = 2^7 - 11^2 = 2^15 - 181^2.

MATHEMATICA

Select[Union[Flatten[Table[2^x - y^2, {x, 16}, {y, 0, Floor[Sqrt[2^x]]}]]], PrimeQ] (* Alonso del Arte, Oct 05 2014 *)

CROSSREFS

Cf. A038198, A051213, A060728, A248344.

Sequence in context: A120302 A093363 A291525 * A236514 A211997 A127581

Adjacent sequences:  A248343 A248344 A248345 * A248347 A248348 A248349

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Oct 05 2014

EXTENSIONS

a(24) - a(38) from Alonso del Arte, Oct 05 2014

STATUS

approved

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Last modified October 23 10:05 EDT 2019. Contains 328345 sequences. (Running on oeis4.)