A274038 Least number k such that the sum of squares of positive divisors of k is the sum of two nonzero squares in exactly n ways.

2, 6, 24, 40, 104, 94, 728, 248, 376, 614, 611394, 584, 1880, 3055, 2632, 1570

Offset: 1

Author

Altug Alkan, Jun 13 2016

Keywords

• nonn
• more

Comments

Least number k such that A001157(k) is the sum of two nonzero squares in exactly n ways.

Additional terms for n > 16: ?, 2914, ?, 2456, 21490, 18330, 13160, 4216, 40152, ?, 11656, 17192, ?, 12280, 156570, 9734, 4306794, ?, 431634, 17954, 411558, 173992, ?, 22922, 77080, 85960... - Lars Blomberg, Sep 20 2017

A001157(a(n)) >= A016032(n). - Max Alekseyev, Feb 02 2025

a(17) >= 10^20 if it exists. - Max Alekseyev, May 15 2025

Examples

			a(2) = 6 because 6 is divisible by 1, 2, 3, 6. 1^2 + 2^2 + 3^2 + 6^2 = 1^2 + 7^2 = 5^2 + 5^2.
		

Crossrefs

Cf. A001157, A016032.

Extensions

a(11) from Giovanni Resta, Jun 13 2016

a(14)-a(16) from Lars Blomberg, Sep 20 2017