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A086884 Smallest string of 1's and 0's which is prime in every base from 2 to n. 1
10, 10, 101111, 10010111, 111110100001, 111110100001, 11000011101101111, 10011110011011110110110011, 110100000010101111110001010011001110001, 1000000010000011110100010001000101001010110111001 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..11.

Phil Carmody, Bitstrings representing primes in many bases.

EXAMPLE

a(5) = 10010111 because 10010111 (base 2) = 151, 10010111 (base 3) = 2281, 10010111 (base 4) = 16661 and 10010111 (base 5) = 78781 are all prime and 10010111 is smallest such string.

MATHEMATICA

a[n_] := (While[b = FromDigits[ IntegerDigits[k, 2]]; Union[ PrimeQ[ Table[ FromDigits[ IntegerDigits[b], i], {i, 2, n}]]] != {True}, k++ ]; b); k = 1; Do[ Print[ a[n]], {n, 2, 10}]

CROSSREFS

See A086204 for decimal equivalents.

Sequence in context: A052983 A072804 A079793 * A284201 A324660 A336035

Adjacent sequences:  A086881 A086882 A086883 * A086885 A086886 A086887

KEYWORD

nonn

AUTHOR

Richard FitzHugh (fitzhughrichard(AT)hotmail.com), Aug 22 2003

EXTENSIONS

Edited by Robert G. Wilson v, Aug 24 2003

a(10) from Phil Carmody's Web site added by Dario Alpern, May 14 2006

Cross-reference changed from A096204 to A086204 James G. Merickel, Nov 18 2009

a(11) from Phil Carmody's website added by James G. Merickel, Feb 15 2010

STATUS

approved

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Last modified April 10 18:49 EDT 2021. Contains 342853 sequences. (Running on oeis4.)