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A173446 ((n+{0,1})-th prime-1)^2+1 are both primes. 0
1, 2, 3, 4, 12, 31, 36, 53, 54, 78, 82, 105, 125, 155, 247, 403, 422, 548, 678, 679, 751, 769, 784, 798, 809, 829, 845, 899, 1049, 1148, 1155, 1312, 1317, 1423, 1436, 1490, 1616, 1688, 1935, 1961, 1990, 1991, 2071, 2181, 2198, 2397, 2437, 2454, 2463, 2556 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers n such that ((n+{0,1})-th prime-1)^2+1 are both primes.

LINKS

Table of n, a(n) for n=1..50.

EXAMPLE

a(1)=1 because ((1+0)-th prime-1)^2+1=2=prime and ((1+1)-th prime-1)^2+1=5=prime; a(2)=2 because ((2+0)-th prime-1)^2+1=5=prime and ((2+1)-th prime-1)^2+1=17=prime

CROSSREFS

Cf. A000040, A006093, A127435, A173444.

Sequence in context: A037397 A168047 A236371 * A053350 A165302 A276530

Adjacent sequences:  A173443 A173444 A173445 * A173447 A173448 A173449

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Feb 18 2010

EXTENSIONS

126 removed. Terms beyond 247 added by R. J. Mathar, Mar 01 2010

STATUS

approved

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Last modified August 26 02:19 EDT 2019. Contains 326324 sequences. (Running on oeis4.)