[go: up one dir, main page]
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A362680 a(n) is the number of decimal digits in A173426(n). 0
1, 3, 5, 7, 9, 11, 13, 15, 17, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80, 84, 88, 92, 96, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 148, 152, 156, 160, 164, 168, 172, 176, 180, 184, 188, 192, 196, 200, 204, 208, 212, 216, 220, 224, 228, 232 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Table of n, a(n) for n=1..63.
FORMULA
a(n) = A058183(n) + A058183(n-1), for n >= 2.
a(n) = A055642(A173426(n)).
a(n) = 2*A058183(n) - A055642(n).
EXAMPLE
a(12)=28 since 1234567891011121110987654321 has 28 digits.
PROG
(PARI)
a(n)={my(t=logint(n, 10)+1); 2*n*t-2*(10^t-1)/9+t}
(Python)
def a(n): return ((n*(t:=len(str(n)))-(10**t-1)//9)<<1) + t
print([a(n) for n in range(1, 64)]) # Michael S. Branicky, May 02 2023
CROSSREFS
Cf. A173426, A058183, A055642.
Sequence in context: A137507 A061808 A248608 * A309325 A368729 A192863
Adjacent sequences: A362677 A362678 A362679 * A362681 A362682 A362683
KEYWORD
nonn,base
AUTHOR
David Cleaver, Apr 29 2023
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 31 22:14 EDT 2024. Contains 375574 sequences. (Running on oeis4.)