Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

1,1

Table of n, a(n) for n=1..72.

F. Ellermann, Some EIS sequences based on a spiral of natural numbers.

Index entries for sequences that are permutations of the natural numbers.

7 8 9 10: ..., a(7)= 8, a(8)= 9, a(9)= 10, ...

6 1 2 11: ..., a(6)= 1, a(1)= 2, a(2)= 11, ... (see A054552, A054567).

5 4 3 12: ..., a(5)= 4, a(4)= 3, a(3)= 12, ...

n = A068226(A068225(n)). Right (left) part of middle row is A054552 (A054567).

Sequence in context: A090009 A153706 A201187 * A043080 A108199 A137904

Adjacent sequences: A068222 A068223 A068224 * A068226 A068227 A068228

nonn,easy

Frank Ellermann, Feb 22 2002

approved