login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A068664 a(1) = 1, a(n) = smallest palindromic multiple of a(n-1). 9
1, 2, 4, 8, 88, 616, 6776, 88088, 616616, 232464232, 21154245112, 232696696232, 21175399357112, 21154245133154245112, 232696696464696696232, 21175399378287399357112, 63386501441764911946714410568336 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..17.

MATHEMATICA

a=1; Print[a]; For[n = 2, n <= 15, n++, {an = a; k = 2; str = ToString[k*an]; rstr = StringReverse[str]; While[str != rstr, {k = k + 1; str = ToString[k*an]; rstr = StringReverse[str]; If[k*an > 10^20, {Print["Too big"]; Abort[]}]}]; a := k*an; Print[k, " ", a]; }]

CROSSREFS

A068667 (from a(3) on) and this sequence (from a(6) on) coincide.

Cf. A068665, A068666, A068667, A068668, A070069, A068971, A068972, A068973, A068974.

Sequence in context: A237913 A076886 A046385 * A199166 A018605 A058262

Adjacent sequences:  A068661 A068662 A068663 * A068665 A068666 A068667

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Mar 01 2002.

EXTENSIONS

Extended and edited by John W. Layman, Mar 18 2002. Last two terms from David W. Wilson and Patrick De Geest, Mar 30 2002.

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 16 17:25 EST 2018. Contains 318172 sequences. (Running on oeis4.)