The On-Line Encyclopedia of Integer Sequences (OEIS)

The OEIS is supported by the many generous donors to the OEIS Foundation.

Revision History for A224841

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

A224841

Triangle T(n,k) read by rows: Substring of k digits of sequence A007376, ending at position n, 1 <= k <= n.
(history; published version)

#13 by Reinhard Zumkeller at Mon Nov 11 10:30:37 EST 2013

STATUS

editing

approved

#12 by Reinhard Zumkeller at Mon Nov 11 07:01:14 EST 2013

LINKS

Reinhard Zumkeller, <a href="/A224841/b224841.txt">Table of n, a(n) for Rows n = 1..7875125 of table, flattened</a>

PROG

(Haskell)

import Data.List (inits, tails)

a224841 n k = a224841_tabl !! (n-1) !! (k-1)

a224841_row n = a224841_tabl !! (n-1)

a224841_tabl = map

(reverse . map (read . concatMap show) . init . tails) $

tail $ inits a007376_list :: [[Integer]]

-- Reinhard Zumkeller, Nov 11 2013

#11 by Reinhard Zumkeller at Mon Nov 11 06:59:38 EST 2013

LINKS

Reinhard Zumkeller, <a href="/A224841/b224841.txt">Table of n, a(n) for n = 1..7875</a>

STATUS

approved

editing

#10 by Bruno Berselli at Mon Jul 22 05:09:31 EDT 2013

STATUS

reviewed

approved

#9 by Joerg Arndt at Mon Jul 22 04:34:28 EDT 2013

STATUS

proposed

reviewed

#8 by M. F. Hasler at Mon Jul 22 00:28:00 EDT 2013

STATUS

editing

proposed

#7 by M. F. Hasler at Mon Jul 22 00:27:35 EDT 2013

KEYWORD

nonn,easy,base,changed,tabl

STATUS

proposed

editing

#6 by M. F. Hasler at Mon Jul 22 00:22:53 EDT 2013

STATUS

editing

proposed

Discussion

Mon Jul 22

00:25

M. F. Hasler: I'm surprised that this very elementary sequence (almost "core"!?) is not yet in OEIS...
NB: the PARI code needs to be improved, it becomes wrong beyond the 9th row of the table.

#5 by M. F. Hasler at Mon Jul 22 00:22:30 EDT 2013

NAME

allocated for M. F. Hasler

Triangle T(n,k) read by rows: Substring of k digits of sequence A007376, ending at position n, 1 <= k <= n.

DATA

1, 2, 12, 3, 23, 123, 4, 34, 234, 1234, 5, 45, 345, 2345, 12345, 6, 56, 456, 3456, 23456, 123456, 7, 67, 567, 4567, 34567, 234567, 1234567, 8, 78, 678, 5678, 45678, 345678, 2345678, 12345678, 9, 89, 789, 6789, 56789, 456789, 3456789, 23456789, 123456789

OFFSET

1,2

COMMENTS

In contrast to sequence A162711, this sequence contains each substring without leading zero of A007376 at least once.

PROG

(PARI) for(i=1, 9, for(j=1, i, for(k=i-j+1, i, print1(k)); print1(", ")))

KEYWORD

allocated

nonn,easy,base

AUTHOR

M. F. Hasler, Jul 22 2013

STATUS

approved

editing

#4 by M. F. Hasler at Mon Jul 22 00:22:30 EDT 2013

NAME

allocated for M. F. Hasler

KEYWORD

recycled

allocated