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A126933 Take the decimal number formed by the first n digits of A023396 in reverse order and divide by 2^n. 2
1, 3, 14, 132, 691, 1908, 16579, 47352, 414301, 1183713, 5474669, 27151397, 135646011, 678174568, 6442602909, 18480090517, 85533990571 (list; graph; refs; listen; history; text; internal format)



The sequence A023396 gives n-digit numbers consisting entirely of 1s and 2s which are divisible by 2^n. The quotients upon division form the present sequence. The parity of the n-th term here determines the next term in A023396; if even, it is a 1 and if odd, a 2.

This was set as a problem in the All Union Mathematical Olympiad of 1971 and can be found in the reference cited here.


J. B. Tabov and P. J. Taylor, Methods of Problem Solving, Book 1, Australian Mathematics Trust, 1996.


Table of n, a(n) for n=1..17.


Sequence in context: A186772 A061029 A096657 * A073550 A002966 A075654

Adjacent sequences:  A126930 A126931 A126932 * A126934 A126935 A126936




Gerry Leversha (g.leversha(AT)btinternet.com), Mar 18 2007



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Last modified December 21 06:19 EST 2014. Contains 252297 sequences.