|
| |
|
|
A072033
|
|
Smallest x such that GCD[2^x, A004086(2^x)=2^n.
|
|
0
| |
|
|
4, 1, 2, 26, 131, 227, 301, 567, 879, 3240, 11051, 8048
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
FORMULA
| a(n)=Min{x; GCD[2^x, Rev[2^x]]=2^n}=Min{x; A055483[x]=2^n}; A072032[a(n)]=2^n.
|
|
|
EXAMPLE
| n=4: a(4)=26 because GCD[2^26,Rev[2^26]]= GCD[67108864,46880176]=16=2^n; Extensions: a(14)=7321,a(17)=6294.
|
|
|
MATHEMATICA
| nd[x_, y_] := 10*x+y tn[x_] := Fold[nd, 0, x] red[x_] := Reverse[IntegerDigits[x]] Table[s=0; g=2^j; Do[s=GCD[2^n, tn[red[2^n]]]; If[Equal[s, g], Print[{n, s}]], {n, 1, 25000}], {j, 1, 25}]
|
|
|
CROSSREFS
| Cf. A055483, A004086, A071686, A072032.
Sequence in context: A110559 A030441 A206359 * A159766 A004161 A202778
Adjacent sequences: A072030 A072031 A072032 * A072034 A072035 A072036
|
|
|
KEYWORD
| more,nonn,base
|
|
|
AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Jun 07 2002
|
| |
|
|
