A342872 Distance to nearest product of 3 consecutive numbers (three-dimensional promic number, A007531).

0, 1, 2, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17

Offset: 0

Author

Lamine Ngom, Mar 28 2021

Keywords

• nonn
• easy

Examples

			a(13) = 7 since 6 is the closest three-dimensional promic to 13 and 13 - 6 = 7.
		

Links

• Lamine Ngom, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A007531, A342873.

Other distance to nearest: A081134, A053646, A201053.

Programs

Python

def a(n): return min(abs(n-k*(k+1)*(k+2)) for k in range(int(n**1/3)+1))
print([a(n) for n in range(78)]) # Michael S. Branicky, Mar 28 2021