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.

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

Offset: 1

Author

Tomas Xordan, May 28 2007

Keywords

• easy
• nonn

Examples

			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.

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)