The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A362680 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A362680

a(n) is the number of decimal digits in A173426(n).
(history; published version)

#20 by Michael De Vlieger at Tue May 02 11:25:35 EDT 2023

STATUS

reviewed

approved

#19 by Michel Marcus at Tue May 02 10:20:31 EDT 2023

STATUS

proposed

reviewed

#18 by Michael S. Branicky at Tue May 02 08:41:36 EDT 2023

STATUS

editing

proposed

#17 by Michael S. Branicky at Tue May 02 08:41:24 EDT 2023

PROG

def a(n): return 2*((n*(t:=len(str(n-1))) - (10**t + -1)//9) + len(str(n)<<1) + t

print([a(n) for n in range(1, 6364)]) # Michael S. Branicky, Apr 29 May 02 2023

STATUS

reviewed

editing

#16 by Kevin Ryde at Tue May 02 06:08:27 EDT 2023

STATUS

proposed

reviewed

#15 by Kevin Ryde at Tue May 02 06:08:17 EDT 2023

STATUS

editing

proposed

#14 by Kevin Ryde at Tue May 02 06:07:55 EDT 2023

FORMULA

a(n) = A058183(n) + A058183(n-1), for n >= 2, and a(1)=1.

STATUS

reviewed

editing

#13 by Michel Marcus at Tue May 02 05:56:01 EDT 2023

STATUS

proposed

reviewed

#12 by David Cleaver at Sun Apr 30 20:43:14 EDT 2023

STATUS

editing

proposed

#11 by David Cleaver at Sun Apr 30 20:33:26 EDT 2023

FORMULA

a(n) = 2*A058183(n) - A055642(n).

PROG

a(n)={my(t=if(n==1, 1, logint(n-1, , 10)+1)); 2*n*t-2*(10^t-1)/9+logint(n, 10)+1t}

STATUS

proposed

editing