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A072037
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Palindromic powers (with positive exponents) of a prime but not a prime (A025475).
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2
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4, 8, 9, 121, 343, 1331, 10201, 14641, 94249, 1030301, 104060401, 900075181570009, 10022212521222001, 12124434743442121, 12323244744232321, 12341234943214321, 1022321210249420121232201, 1210024420147410244200121, 1210222232227222322220121
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..19.
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EXAMPLE
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E.g. 94249=307*307
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MATHEMATICA
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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)
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PROG
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(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], ", "))}
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CROSSREFS
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Cf. A025475, A002385.
Sequence in context: A046450 A077271 A084093 * A076703 A141220 A108806
Adjacent sequences: A072034 A072035 A072036 * A072038 A072039 A072040
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KEYWORD
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base,easy,nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jun 07 2002
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EXTENSIONS
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Two more term from Klaus Brockhaus, Jun 07 2002
Four more terms from Robert G. Wilson v, Oct 31 2002
Added a(17)-a(19), clarified definition, Donovan Johnson, Sep 01 2012
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STATUS
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approved
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