A379346 Number of integers of the form k^2 + 1 whose greatest prime factor is A002313(n), the n-th prime not congruent to 3 mod 4.

1, 3, 5, 6, 7, 10, 9, 16, 17, 20, 26, 36, 36, 40, 46, 47, 56, 67, 73, 86, 97, 107

Offset: 1

Author

Andrew Howroyd, Dec 22 2024

Keywords

• nonn
• more

Comments

See A223702 for additional information.

Links

• Florian Luca, Primitive divisors of Lucas sequences and prime factors of x^2 + 1 and x^4 + 1, Acta Academiae Paedagogicae Agriensis, Sectio Mathematicae 31 (2004), pp. 19-24.
• Filip Najman, Smooth values of some quadratic polynomials, Glasnik Matematicki Series III 45 (2010), pp. 347-355.

Crossrefs

Row lengths of A223702.

First differences of A285283.

Cf. A002313, A177979, A185389.