A067912
Engel expansion of zeta(4) = Pi^4/90 = Sum_{i>0} 1/i^4.
Original entry on oeis.org
1, 13, 15, 19, 132, 1474, 1977, 10392, 12992, 44777, 59412, 170685, 217607, 704791, 818133, 1387423, 2208674, 3206215, 12732462, 13962681, 24593168, 39744274, 55804517, 130269696, 426536424, 546807194, 1030799587, 1139987135
Offset: 1
See
A006784 for explanation of Engel expansions.
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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[Pi^4/90, 7!], 20] (* G. C. Greubel, Dec 26 2016 *)
A059186
Engel expansion of Pi^2/6, or zeta(2) = 1.64493.
Original entry on oeis.org
1, 2, 4, 7, 9, 22, 35, 79, 2992, 3597, 17523, 28632, 41470, 53093, 57406, 14504930, 42622213, 188335162, 322429556, 1023003875, 1328535963, 3138645732, 11618168524, 137721814936, 156929353744, 166732460513, 813398686532
Offset: 1
- F. Engel, Entwicklung der Zahlen nach Stammbruechen, Verhandlungen der 52. Versammlung deutscher Philologen und Schulmaenner in Marburg, 1913, pp. 190-191.
- 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.
- 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.
- Index entries for sequences related to Engel expansions
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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[Pi^2/6, 7!], 100] (* Modified by G. C. Greubel, Dec 27 2016 *)
Showing 1-2 of 2 results.
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