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A004665
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Powers of 3 written in base 11. (Next term contains a non-decimal character.)
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1
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OFFSET
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0,2
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COMMENTS
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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
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LINKS
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MATHEMATICA
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FromDigits[IntegerDigits[#, 11]]&/@(3^Range[0, 7]) (* Harvey P. Dale, Jul 31 2013 *)
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PROG
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(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
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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