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Search: id:A130474
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A130474 Prime numbers p of the form p=x^2+y^3 such that q =A130475(n)= abs(x^2-y^3) is prime and smaller than p. +0
2
5, 31, 43, 89, 127, 241, 269, 283, 379, 449, 449, 487, 521, 593, 811, 919, 953, 1009, 1051, 1601, 2017, 2089, 2089, 2143, 2341, 2521, 2521, 2609, 2731, 2953, 3041, 3163, 3391, 3631, 3943, 4051, 4129, 4159, 4481, 4481, 4651, 4931, 4969, 5113, 5209, 5309 (list; graph; listen)
OFFSET

1,1

FORMULA

a(n)= x^2+y^3 and A130475(n)=q=abs(x^2-y^3); a(n) > A130475(n);a(n) and A130475(n) are in A000040 (prime numbers)

EXAMPLE

a(4)= 89 because 89= 9^2+2^3= 81 + 8 and A130475(4)= 73 =abs(9^2-2^3)= abs(81-8) ; A130475(4) < a(4) ; A130475(4) and a(4) are prime numbers, members of A000040.

a(5)= 127 because 127= 10^2+ 3^3= 100 + 27 and A130475(5)= 73 = abs(10^2-3^3)= abs(100-27) ; A130475(5) < a(5) ; A130475(5) and a(5) are prime numbers, members of A000040.

a(9)= 379 because 379= 6^2 + 7^3= 36 + 343 and A130475(9)= 307 = abs(6^2-7^3)= abs(36-343) ; A130475(9) < a(9) ; A130475(9) and a(9) are prime numbers, members of A000040.

CROSSREFS

Cf. A000040; A130475.

Adjacent sequences: A130471 A130472 A130473 this_sequence A130475 A130476 A130477

Sequence in context: A058783 A042837 A027761 this_sequence A125743 A078686 A031908

KEYWORD

easy,nonn

AUTHOR

Tomas Xordan (xordan.tom(AT)gmail.com), May 28 2007

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Last modified October 7 14:39 EDT 2008. Contains 144666 sequences.


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