The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A049649 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A049649

T(n,n+3), array T given by A049639.
(history; published version)

#19 by OEIS Server at Fri Aug 06 17:31:21 EDT 2021

LINKS

Sean A. Irvine, <a href="/A049649/b049649_1.txt">Table of n, a(n) for n = 0..500</a> (terms 1..76 from G. C. Greubel)

#18 by Alois P. Heinz at Fri Aug 06 17:31:21 EDT 2021

STATUS

proposed

approved

Discussion

Fri Aug 06

17:31

OEIS Server: Installed new b-file as b049649.txt.  Old b-file is now b049649_1.txt.

#17 by Sean A. Irvine at Fri Aug 06 15:57:55 EDT 2021

STATUS

editing

proposed

Discussion

Fri Aug 06

17:31

Alois P. Heinz: yes ... thanks

#16 by Sean A. Irvine at Fri Aug 06 15:57:37 EDT 2021

LINKS

G. CSean A. Greubel, Irvine, <a href="/A049649/b049649_1.txt">Table of n, a(n) for n = 0..75500</a> (terms 1..76 from G. C. Greubel)

STATUS

proposed

editing

Discussion

Fri Aug 06

15:57

Sean A. Irvine: b-file updated

#15 by Sean A. Irvine at Fri Aug 06 00:50:07 EDT 2021

STATUS

editing

proposed

Discussion

Fri Aug 06

01:46

Michel Marcus: name should be T(n+3,n) ?

01:47

Michel Marcus: b-file wants same data change ?

02:03

Michel Marcus: 01:46 : no, sorry T is an array (A049639 should rather show the array than he diagonals)

13:55

Alois P. Heinz: existing b-file is not consistent with data ... so this cannot be published as it is ...

#14 by Sean A. Irvine at Fri Aug 06 00:50:02 EDT 2021

DATA

1, 1, 4, 5, 7, 8, 11, 14, 17, 18, 23, 28, 31, 34, 41, 46, 51, 54, 61, 70, 75, 78, 89, 100, 105, 110, 123, 130, 137, 144, 153, 168, 177, 182, 199, 216, 223, 230, 249, 260, 269, 278, 291, 312, 323, 330, 353, 372, 381, 392, 413, 430, 443, 454, 473, 500, 513, 520, 549, 578, 587, 602

OFFSET

0,23

MATHEMATICA

T[0 | 1, 0 | 1] = 0; T[0 | 1, _] = T[_, 0 | 1] = 1; T[i_, j_] := Module[{slopes, cnt}, slopes = Union@Flatten@Table[(k - j)/(h - i), {h, 0, i - 1}, {k, 0, j - 1}]; cnt[slope_] := Count[Flatten[Table[{h, k}, {h, 0, i - 1}, {k, 0, j - 1}], 1], {h_, k_} /; (k - j)/(h - i) == slope]; Count[cnt /@ slopes, c_ /; c >= 2] + 2]; Table[T[n, n + 3], {n, 1, 0, 50}] (* G. C. Greubel, Dec 05 2017 *)

EXTENSIONS

Missing a(0)=1 inserted by Sean A. Irvine, Aug 06 2021

STATUS

approved

editing

#13 by Peter Luschny at Mon Dec 11 05:05:30 EST 2017

STATUS

reviewed

approved

#12 by Michel Marcus at Mon Dec 11 03:15:22 EST 2017

STATUS

proposed

reviewed

#11 by Wesley Ivan Hurt at Sun Dec 10 16:57:50 EST 2017

STATUS

editing

proposed

#10 by Wesley Ivan Hurt at Sun Dec 10 16:57:34 EST 2017

CROSSREFS

Cf. A049639.

STATUS

proposed

editing