A358540 a(n) is the smallest number with exactly n divisors that are n-gonal pyramidal numbers.

56, 140, 1440, 11550, 351120, 41580, 742560, 29279250, 8316000, 72348396120, 3386892600, 578918340

Offset: 3

Author

Ilya Gutkovskiy, Nov 21 2022

Keywords

• nonn
• more

Comments

Any subsequent terms are > 2 * 10^9. - Lucas A. Brown, Dec 24 2022

Examples

			a(5) = 1440 because 1440 has 5 pentagonal pyramidal divisors {1, 6, 18, 40, 288} and this is the smallest such number.
		

Links

• Lucas A. Brown, Python program.
• Eric Weisstein's World of Mathematics, Pyramidal Number
• Index entries for sequences related to divisors of numbers

Crossrefs

Cf. A005179, A358539, A358541, A358542, A358543.

Extensions

a(11)-a(13) from Martin Ehrenstein, Dec 02 2022

a(14) from Lucas A. Brown, Dec 19 2022