A324593 a(n) is the smallest number k such that n consecutive integers starting at k have the same number of odd divisors (A001227).

1, 1, 5, 10, 10, 515, 2314, 2314, 1536863, 4053992, 4053992, 18584686, 146237365, 163039279, 4775943486, 13147233734, 86153130379

Offset: 1

Author

Ilya Gutkovskiy, Sep 03 2019

Keywords

• nonn
• more

Examples

			515 has 4 odd divisors {1, 5, 103, 515}, 516 has 4 odd divisors {1, 3, 43, 129}, 517 has 4 odd divisors {1, 11, 47, 517}, 518 has 4 odd divisors {1, 7, 37, 259}, 519 has 4 odd divisors {1, 3, 173, 519} and 520 has 4 odd divisors {1, 5, 13, 65}. These the first 6 consecutive numbers with the same number of odd divisors, so a(6) = 515.
		

Links

• Rémy Sigrist, C program for A324593

Crossrefs

Cf. A001227, A006558, A045983, A045984, A323253, A324594.

Programs

C

See Links section.

Extensions

a(11)-a(14) from Rémy Sigrist, Sep 04 2019

a(15)-a(17) from Giovanni Resta, Sep 04 2019