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A049649 T(n,n+3), array T given by A049639. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
Sean A. Irvine, Table of n, a(n) for n = 0..500 (terms 1..76 from G. C. Greubel)
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, 0, 50}] (* G. C. Greubel, Dec 05 2017 *)
CROSSREFS
Cf. A049639.
Sequence in context: A120753 A188322 A139201 * A050575 A081452 A047492
KEYWORD
nonn
AUTHOR
EXTENSIONS
Terms a(37) onward added by G. C. Greubel, Dec 10 2017
Missing a(0)=1 inserted by Sean A. Irvine, Aug 06 2021
STATUS
approved

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Last modified March 19 01:34 EDT 2024. Contains 370952 sequences. (Running on oeis4.)