|
|
A181385
|
|
Maximal number that can be obtained by reversing n in an integer base.
|
|
2
|
|
|
0, 1, 2, 3, 4, 7, 9, 13, 16, 21, 25, 31, 36, 43, 49, 57, 64, 73, 81, 91, 100, 111, 121, 133, 144, 157, 169, 183, 196, 211, 225, 241, 256, 273, 289, 307, 324, 343, 361, 381, 400, 421, 441, 463, 484, 507, 529, 553, 576, 601, 625, 651, 676, 703, 729, 757, 784, 813, 841
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
The second differences of this sequence start with 2 zeros and then seem to alternate between 2 and -1 perpetually
The bases which yield the first five numbers on this list are {{2},{3},{2,4},{3,5},{3}}, where multiple items on the sublists indicate multiple bases yielding the same maximum. 3 and 4 seem to be the only 2 numbers with multiple bases that yield the same maximum. The numbers of the bases which yield numbers on this list for values n greater than 5 seem to be Floor((n+2)/2).
|
|
LINKS
|
|
|
MATHEMATICA
|
rev[x_, b_]:=FromDigits[Reverse[IntegerDigits[x, b]], b]
Max /@ Table[Table[rev[x, b], {b, 2, x + 1}], {x, STARTPOINT, ENDPOINT}]
|
|
PROG
|
(PARI) a(n) = vecmax(apply(b -> fromdigits(Vecrev(digits(n, b)), b), [2..max(2, n+1)])) \\ Rémy Sigrist, Jan 29 2020
|
|
CROSSREFS
|
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|