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, 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

Offset

1,1

Links

Table of n, a(n) for n=1..39.

Example

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.

Sequence in context: A169893 A169899 A328040 * A324495 A087276 A138225

Adjacent sequences: A075770 A075771 A075772 * A075774 A075775 A075776

Keyword

nonn

Author

Neil Fernandez, Oct 09 2002

Status

approved