The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A136306 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A136306

a(n) = a(n-1)*(10^K) + n*a(n-1); a(0)=1; K=floor(log_10 (n*a(n-1))).
(history; published version)

#9 by Michael De Vlieger at Wed Mar 16 10:33:44 EDT 2022

STATUS

reviewed

approved

#8 by Joerg Arndt at Wed Mar 16 05:22:50 EDT 2022

STATUS

proposed

reviewed

#7 by Michel Marcus at Wed Mar 16 05:05:40 EDT 2022

STATUS

editing

proposed

#6 by Michel Marcus at Wed Mar 16 05:05:24 EDT 2022

NAME

a(n) = a(n-1)*(10^K) + n*a(n-1); a(0)=1; K=floor(log_10 (n*a(n-1))).

DATA

1, 2, 6, 78, 8112, 81160560, 8116056486963360, 81160564869633656812395408743520, 8116056486963365681239540874352649284518957069254499163269948160

PROG

(PARI) a(n) = if (n==0, 1, my(x=a(n-1), K=log(n*x)\log(10)); x*(10^K) + n*x); \\ Michel Marcus, Mar 16 2022

EXTENSIONS

Offset corrected. - _ by _R. J. Mathar_, Jun 19 2021

More terms from Michel Marcus, Mar 16 2022

STATUS

approved

editing

Discussion

Wed Mar 16

05:05

Michel Marcus: next term is too large

#5 by R. J. Mathar at Sat Jun 19 13:38:42 EDT 2021

STATUS

editing

approved

#4 by R. J. Mathar at Sat Jun 19 13:38:30 EDT 2021

NAME

a(n)=a(n-1)*(10^K) + n*a(n-1); a(0)=1; K=floor(log_10 (n*a(n-1))).

OFFSET

1,0,2

MAPLE

A136306 := proc(n)

option remember;

local k ;

if n = 0 then

1;

else

if n*procname(n-1) < 1 then

k := 0;

else

k := floor(log[10](n*procname(n-1))) ;

end if ;

procname(n-1)*(n+10^k) ;

end if;

end proc:

seq(A136306(n), n=0..10) ; # R. J. Mathar, Jun 19 2021

EXTENSIONS

Offset corrected. - R. J. Mathar, Jun 19 2021

STATUS

approved

editing

#3 by R. J. Mathar at Wed Jun 26 05:46:52 EDT 2013

STATUS

editing

approved

#2 by R. J. Mathar at Wed Jun 26 05:46:48 EDT 2013

AUTHOR

_Ctibor O. ZIZKA (ctibor.zizka(AT)seznam.cz), Zizka_, Mar 22 2008

STATUS

approved

editing

#1 by N. J. A. Sloane at Sun Jun 29 03:00:00 EDT 2008

NAME

a(n)=a(n-1)*(10^K) + n*a(n-1); a(0)=1; K=floor(log_10 n*a(n-1)).

DATA

1, 2, 6, 78, 8112, 81160560

OFFSET

1,2

COMMENTS

Sequence generalized :

a(n)=[a(n-1)*B^F(a(n-1),n)]+G(a(n-1),n); a(0)=1; F(t),G(t)integer functions.

FORMULA

a(n)=a(n-1)*(10^K) + n + a(n-1); a(0)=1; K=floor(log_10 n + a(n-1)) + 1.

KEYWORD

easy,nonn

AUTHOR

Ctibor O. ZIZKA (ctibor.zizka(AT)seznam.cz), Mar 22 2008

STATUS

approved