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A007377
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Numbers n such that decimal expansion of 2^n contains no 0.
(Formerly M0485)
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37
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1, 2, 3, 4, 5, 6, 7, 8, 9, 13, 14, 15, 16, 18, 19, 24, 25, 27, 28, 31, 32, 33, 34, 35, 36, 37, 39, 49, 51, 67, 72, 76, 77, 81, 86
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| It is an open problem of long standing to show that 86 is the last term.
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REFERENCES
| J. S. Madachy, Mathematics on Vacation, Scribner's, NY, 1966, p. 126.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| W. Schneider, NoZeros: Powers n^k without Digit Zero [Cached copy]
Eric Weisstein's World of Mathematics, Zero
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MATHEMATICA
| Do[ If[ Union[ RealDigits[ 2^n ] [[1]]] [[1]] != 0, Print[ n ] ], {n, 1, 60000}]
Select[Range@1000, First@Union@IntegerDigits[2^# ] != 0 &]
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PROG
| (MAGMA) [ n: n in [1..50000] | not 0 in Intseq(2^n) ]; // Bruno Berselli, Jun 08 2011
(Perl) use bignum;
for(1..99) {
if((1<<$_) =~ /^[1-9]+$/) {
print "$_, "
}
} # Charles R Greathouse IV, Jun 30 2011
(PARI) for(n=1, 99, if(vecmin(eval(Vec(Str(2^n)))), print1(n", "))) \\ Charles R Greathouse IV, Jun 30 2011
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CROSSREFS
| Cf. A027870, A102483.
Sequence in context: A032973 A174887 A092598 * A135140 A052061 A045540
Adjacent sequences: A007374 A007375 A007376 * A007378 A007379 A007380
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KEYWORD
| base,nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Robert G. Wilson v (rgwv(AT)rgwv.com)
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