Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A072037
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A072037 Palindromic powers of a prime but not a prime (A025475). +0
3
4, 8, 9, 121, 343, 1331, 10201, 14641, 94249, 1030301, 104060401, 900075181570009, 10022212521222001, 12124434743442121, 12323244744232321, 12341234943214321 (list; graph; listen)
OFFSET

1,1

EXAMPLE

E.g. 94249=307*307

MATHEMATICA

a = {}; Do[pp = Prime[n]^i; d = IntegerDigits[pp]; If[d == Reverse[d], a = Append[a, pp]], {n, 1, PrimePi[ Sqrt[10^21]]}, {i, 2, Floor[ Log[ Prime[n], 10^21]]}]; Sort[a] (Robert G. Wilson v)

PROGRAM

(PARI) {a=10^15; v=[]; m=sqrt(a); forprime(p=2, m, q=p; while((q=q*p)<a, n=q; rev=0; while(n>0, d=divrem(n, 10); n=d[1]; rev=10*rev+d[2]); if(q==rev, v=concat(v, q)))); v=vecsort(v); for(j=1, matsize(v)[2], print1(v[j], ", "))}

CROSSREFS

Cf. A025475, A002385.

Sequence in context: A075786 A046450 A077271 this_sequence A084093 A076703 A141220

Adjacent sequences: A072034 A072035 A072036 this_sequence A072038 A072039 A072040

KEYWORD

base,easy,nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Jun 07 2002

EXTENSIONS

Two more term from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 07 2002

Four more terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 31 2002

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified December 16 17:18 EST 2009. Contains 170825 sequences.


AT&T Labs Research