A327825 "Rotation" of n: swap the first [d/2] and last [d/2] digits, when n has d digits.

979, 89, 189, 289, 389, 489, 589, 689, 789, 889, 989, 99, 199, 299, 399, 499, 599, 699, 799, 899, 999, 10, 110, 210, 310, 410, 510, 610, 710, 810, 910, 1010, 1110, 1210, 1310, 1410, 1510, 1610, 1710, 1810, 1910, 2010, 2110, 2210, 2310, 2410, 2510, 2610, 2710, 2810, 2910, 3010, 3110, 3210

Offset: 979

Author

M. F. Hasler, Sep 26 2019

Keywords

• nonn
• base

Comments

When n has an odd number of digits, the middle one remains at its place.

This operation, denoted "rotation" k -> rot(k) in sequences A086002, A086003, A086004, is indistinguishable from A004086 (reverse n) for numbers < 1000. Therefore the offset is chosen as to have 2/3 of the displayed terms beyond this limit and 1/3 below. This makes it easy to find the sequence searching for the terms near that limit, ..., 999, 10, 110, 210,....

Examples

			a(123) = concat(3, 2, 1) = 321.
a(1234) = concat(34, 12) = 3412.
a(12345) = concat(45, 3, 12) = 45312.
		

Crossrefs

Cf. A086002, A086003, A086004, A004086.

Programs

PARI

a(n)={n=digits(n); fromdigits(concat([n[#n\/2+1..#n],n[#n\2+1..#n\/2],n[1..#n\2]]))}

Formula

a(n) = A004086(n) ("reverse n") for n < 1000.