Rob_Gandy 2 Report post Posted September 7, 2012 (edited) What is the missing number in the sequence? 0, 1, 6, 105, 27 030,_______________, 7 608 434 000 728 254 870 The sequence here may seem unusual, but examination may reveal obvious steps required to solve for each element in it. The method to find each term is actually pretty 'basic.' Edited September 7, 2012 by Rob_Gandy Quote Share this post Link to post Share on other sites
0 Rainman 14 Report post Posted September 8, 2012 We are building a binary string, starting with 0. We get the next string by switching all zeros and ones, then adding the switched string at the end of the original string. 0 (switch zeros and ones to get 1, add this at the end of the string to get the next number) 01 (switch zeros and ones to get 10, add this at the end to get...) 0110 (switch to get 1001, add to get...) 01101001 (switch to get 10010110, add to get...) 0110100110010110 (switch to get 1001011001101001, add to get...) 01101001100101101001011001101001 (this is the missing string, bring it back to decimal base to get 1,771,476,589) 1 Quote Share this post Link to post Share on other sites
0 bonanova 83 Report post Posted September 8, 2012 We are building a binary string, starting with 0. We get the next string by switching all zeros and ones, then adding the switched string at the end of the original string. 0 (switch zeros and ones to get 1, add this at the end of the string to get the next number) 01 (switch zeros and ones to get 10, add this at the end to get...) 0110 (switch to get 1001, add to get...) 01101001 (switch to get 10010110, add to get...) 0110100110010110 (switch to get 1001011001101001, add to get...) 01101001100101101001011001101001 (this is the missing string, bring it back to decimal base to get 1,771,476,589) Impressive. Good puzzle, great solve! Quote Share this post Link to post Share on other sites
What is the missing number in the sequence?
0, 1, 6, 105, 27 030,_______________, 7 608 434 000 728 254 870
The sequence
here may seem
unusual, but
examination
may reveal
obvious steps
required to
solve for each
element in it.
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