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A036238 Triangle of numbers a(r,j) = j*(j+1) mod r+2, r>=1, j=1..r. 1
2, 2, 2, 2, 1, 2, 2, 0, 0, 2, 2, 6, 5, 6, 2, 2, 6, 4, 4, 6, 2, 2, 6, 3, 2, 3, 6, 2, 2, 6, 2, 0, 0, 2, 6, 2, 2, 6, 1, 9, 8, 9, 1, 6, 2, 2, 6, 0, 8, 6, 6, 8, 0, 6, 2, 2, 6, 12, 7, 4, 3, 4, 7, 12, 6, 2, 2, 6, 12, 6, 2, 0, 0, 2, 6, 12, 6, 2, 2, 6, 12, 5, 0, 12, 11, 12, 0, 5, 12, 6, 2, 2, 6, 12, 4, 14, 10, 8, 8, 10, 14, 4, 12, 6, 2 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

C. A. Pickover, The Dudley Triangle", Ch. 59 in Wonders of Numbers: Adventures in Mathematics, Mind, and Meaning, Oxford, England: Oxford University Press, pp. 144-145, 2001.

LINKS

Alois P. Heinz, Rows n = 1..200, flattened

U. Dudley, Problem 1277: An infinite triangular array, Math. Mag., 60 (1987), p. 328.

EXAMPLE

Triangle starts:

2;

2,2;

2,1,2;

2,0,0,2;

2,6,5,6,2;

2,6,4,4,6,2;

2,6,3,2,3,6,2;

...

MATHEMATICA

Table[Mod[j (j + 1), r + 2], {r, 14}, {j, r}] // Flatten (* Michael De Vlieger, Sep 23 2015 *)

PROG

(C) #include <stdio.h> #include <stdlib.h> #define MAX_ROWS 100 #define USAGE "Usage: 'A036238 num' where num is the last row of the triangle to compute\n" int main(int argc, char *argv[]) { unsigned long i, j, end, ans; if (argc < 2) { fprintf(stderr, USAGE); return EXIT_FAILURE; } end = atoi(argv[1]); end = (end >= MAX_ROWS) ? MAX_ROWS: end; fprintf(stdout, "Values: "); for (i = 1; i <= end; i++) { for (j = 1; j <= i; j++) { ans = j * (j + 1) % (i +2); fprintf(stdout, "%ld, ", ans); } } fprintf(stdout, "\n"); return EXIT_SUCCESS; } /* Larry Reeves (larryr(AT)acm.org), Mar 31 2000 */

(PARI) tabl(nn) = {for (n=1, nn, for (k=1, n, print1(k*(k+1) % (n+2), ", "); ); print(); ); } \\ Michel Marcus, Sep 23 2015

CROSSREFS

Sequence in context: A232800 A248380 A090044 * A225180 A276134 A229895

Adjacent sequences:  A036235 A036236 A036237 * A036239 A036240 A036241

KEYWORD

nonn,look,easy,tabl

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Mar 31 2000

STATUS

approved

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Last modified December 10 23:07 EST 2016. Contains 279021 sequences.