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A159862 Diagonal of A159861. 2
1, 1, 4, 29, 2265, 18698645, 1602308616574727, 14017675267522095175220940844027, 1245902734717669791621141496863001384336371908521990690157218737 (list; graph; refs; listen; history; text; internal format)



The length (number of decimal digits) of a(n) may be a power of 2 and often simply doubles, when n is increased by 1. But there are many exceptions: n = 11, 12, 13 give lengths 2^8, 3*2^7, 2^9, respectively. A factor of 3 is found in the lengths of a(n) for n = 12, 112..123, 1113..1234, 11123..12345, and so on. A factor of 7 is found for n = 1112, 11112..11122, and so on. 15 is factor of the length of a(11111112).


Alois P. Heinz, Table of n, a(n) for n = 1..12


R:= (S, m)-> iquo (S+m-1, m): A:= proc (m, n) option remember; `if`(n=1, 1, R (parse (cat (seq (A (m, j), j=1..n-1))), m)) end: a:= n-> A(n, n): seq(a(n), n=1..10);


Cf. A156146, A156147, A000040, A010783.

Sequence in context: A166168 A126559 A213795 * A164820 A022387 A108559

Adjacent sequences:  A159859 A159860 A159861 * A159863 A159864 A159865




Eric Angelini and Alois P. Heinz, Apr 24 2009



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Last modified December 20 12:05 EST 2014. Contains 252241 sequences.