A085355 a(n) is the difference between A084321(n) and the (n-1)th power of 2.

0, 1, 1, 2, 3, 3, 0, 11, 0, 24, 37, 47, 73, 90, 133, 135, 110, 133, 435, 795, 317, 1674, 1217, 1975, 4816, 6177, 9483, 11885, 17724, 19562, 22958, 39870, 48417, 85452, 114676, 210482, 133092, 194048, 524165, 451743, 1145779, 1292884, 1604772, 2859433, 4032594

Offset: 1

Author

Labos Elemer and Robert G. Wilson v, Jun 24 2003

Keywords

• nonn

Comments

A084321 is the least number k such that between k! and (k+1)! there are n powers of 2.

Links

• Kevin Ryde, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A084321.

Programs

Mathematica

LogBase2Stirling[n_] := Floor[ Log[2, 2 Pi n]/2 + n*Log[2, n/E] + Log[2, 1 + 1/(12n) + 1/(288n^2) - 139/(51840n^3) - 571/(2488320n^4) + 163879/(209018880n^5)]]; Do[k = 2^(n - 1); While[ LogBase2Stirling[k + 1] - LogBase2Stirling[k] < n, k++ ]; a[n] = k, {n, 1, 45}]; Table[ a[n] - 2^(n - 1), {n, 1, 45}]