A075773 Let {b(n)} be the sequence of perfect powers (A001597); then a(n) = max { b(n)-b(n-1), b(n+1)-b(n) }.

3, 4, 4, 7, 9, 9, 5, 5, 13, 15, 17, 19, 21, 21, 4, 16, 25, 27, 27, 20, 18, 18, 33, 35, 35, 19, 39, 41, 43, 43, 28, 47, 49, 51, 53, 55, 57, 59, 61, 61, 39, 65, 67, 69, 71, 71, 38, 75, 77, 79, 81, 81, 47, 85, 87, 89, 89, 68, 71, 71, 12, 95, 97, 99, 101, 103, 103

Offset: 1

Author

Neil Fernandez, Oct 09 2002

Keywords

• nonn

Examples

			The perfect powers are 1, 4, 8, 9, 16, 25, 27, 32, 36, 49, 64, 81, 100, 121, etc. The 7th is 27. This is 2 larger than the 6th (25) and 5 smaller than the 8th (32). So a(7)=5.
		

Crossrefs

Cf. A001597, A053289, A075772.

Extensions

Missing 4 inserted and more terms from Sean A. Irvine, Mar 06 2025