login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A059180
Engel expansion of log(2).
3
2, 3, 7, 9, 104, 510, 1413, 2386, 40447, 87110, 124975, 1565154, 1766158, 2440919, 2637001, 9192874, 24998746, 73973182, 88828340, 432049320, 470421590, 477600793, 3313014448, 4571423959, 28839435286, 40818751774
OFFSET
1,1
COMMENTS
See A006784 for the definition of Engel expansion.
REFERENCES
F. Engel, Entwicklung der Zahlen nach Stammbruechen, Verhandlungen der 52. Versammlung deutscher Philologen und Schulmaenner in Marburg, 1913, pp. 190-191.
LINKS
G. C. Greubel and T. D. Noe, Table of n, a(n) for n = 1..1000[Terms 1 to 300 computed by T. D. Noe; Terms 301 to 1000 computed by G. C. Greubel, Dec 27 2016]
F. Engel, Entwicklung der Zahlen nach Stammbruechen, Verhandlungen der 52. Versammlung deutscher Philologen und Schulmaenner in Marburg, 1913, pp. 190-191. English translation by Georg Fischer, included with his permission.
Eric Weisstein's World of Mathematics, Engel Expansion
Eric Weisstein's World of Mathematics, Natural Logarithm of 2
P. Erdős and Jeffrey Shallit, New bounds on the length of finite Pierce and Engel series, Sem. Theor. Nombres Bordeaux (2) 3 (1991), no. 1, 43-53.
MATHEMATICA
EngelExp[A_, n_] := Join[Array[1 &, Floor[A]], First@Transpose@
NestList[{Ceiling[1/Expand[#[[1]] #[[2]] - 1]], Expand[#[[1]] #[[2]] - 1]/1} &, {Ceiling[1/(A - Floor[A])], (A - Floor[A])/1}, n - 1]];
EngelExp[N[Log[2], 7!], 100] (* Modified by G. C. Greubel, Dec 27 2016 *)
CROSSREFS
Cf. A002162 (decimal expansion of the natural logarithm of 2).
Sequence in context: A107861 A109800 A152136 * A051637 A051471 A140794
KEYWORD
nonn,easy,nice
AUTHOR
STATUS
approved