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%I #15 Feb 22 2019 01:34:48
%S 1,3,9,25,74,201,603,1709
%N Powers of 3 written in base 11. (Next term contains a non-decimal character.)
%C The next term contains a non-decimal character if such a character (e.g., 'A') is chosen to represent a digit 10, where "digit" means the coefficients in N = Sum_{k>=0} d_k * 11^k. A different "encoding" has to be used to represent such terms in the Data sections of OEIS entries. In order to preserve the terms a(0..7), one could use the two-digit combinations '08' and '18' to encode the digits 8 (the only one not occurring so far) and 10. - _M. F. Hasler_, Jun 25 2018
%t FromDigits[IntegerDigits[#,11]]&/@(3^Range[0,7]) (* _Harvey P. Dale_, Jul 31 2013 *)
%o (PARI) apply( A004665(n)=if(vecmax(n=digits(3^n, 11))>9, Strchr(apply(d->48+d+(d>9)*7,n)), fromdigits(n)), [0..10]) \\ Slightly shorter but slower: {a(n)=iferr(eval(n=Strchr(apply(d->48+d+(d>9)*7,digits(3^n, 11)))),E,n)}. - _M. F. Hasler_, Jun 25 2018
%K nonn,base
%O 0,2
%A _N. J. A. Sloane_
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