|
| |
|
|
A098780
|
|
First n numbers in binary representation concatenated in reverse order.
|
|
7
|
|
|
|
1, 5, 29, 157, 1437, 13725, 128413, 1176989, 20051357, 355595677, 6261175709, 109340390813, 1896046785949, 32682372363677, 560447953696157, 9567647208437149, 315812421869630877, 10692105963331253661
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
Indranil Ghosh, Table of n, a(n) for n = 1..412
Index entries for sequences related to Most Wanted Primes video
|
|
|
FORMULA
|
a(n) = n*A000079(A070939(a(n-1))) + a(n-1); a(1) = 1.
a(n) = n*2^(1 + floor(log_2(a(n-1)))) + a(n-1); a(1) = 1.
|
|
|
EXAMPLE
|
a(4) = (4 3 2 1) -> (100 11 10 1) -> 10011101 -> 157.
|
|
|
MATHEMATICA
|
Table[FromDigits[Flatten[IntegerDigits[#, 2]&/@Reverse[Range[n]]], 2], {n, 20}] (* Harvey P. Dale, Sep 10 2019 *)
|
|
|
PROG
|
(Python)
def A098780(n):
....s=""
....for i in range(n, 0, -1):
........s+=bin(i)[2:]
....return int(s, 2) # Indranil Ghosh, Jan 28 2017
(Python)
from functools import reduce
def A098780(n): return reduce(lambda i, j:(i<<j.bit_length())+j, range(n, 0, -1)) # Chai Wah Wu, Feb 26 2023
|
|
|
CROSSREFS
|
Cf. A007088, A047778.
Sequence in context: A320089 A239715 A260752 * A222700 A272940 A146178
Adjacent sequences: A098777 A098778 A098779 * A098781 A098782 A098783
|
|
|
KEYWORD
|
nonn,base
|
|
|
AUTHOR
|
Reinhard Zumkeller, Oct 04 2004
|
|
|
EXTENSIONS
|
Typo in data corrected by D. S. McNeil, Aug 20 2010
|
|
|
STATUS
|
approved
|
| |
|
|
