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A059399
Triangular hopscotch.
1
1, 3, 2, 6, 4, 5, 10, 7, 9, 8, 15, 11, 14, 12, 13, 21, 16, 20, 17, 19, 18, 28, 22, 27, 23, 26, 24, 25, 36, 29, 35, 30, 34, 31, 33, 32, 45, 37, 44, 38, 43, 39, 42, 40, 41, 55, 46, 54, 47, 53, 48, 52, 49, 51, 50, 66, 56, 65, 57, 64, 58, 63, 59, 62, 60, 61
OFFSET
1,2
LINKS
FORMULA
Write down triangle with rows 1; 2, 3; 4, 5, 6; 7, 8, 9, 10; ...; read rows alternately from right and left ends.
PROG
(PARI) { n=0; for (i = 1, 141, d=i; s=1; for (j=1, i, if (j==1, a=(i^2 + i)/2, a+=s*d); write("b059399.txt", n++, " ", a); d--; s=-s; ); ) } \\ Harry J. Smith, Jun 26 2009
CROSSREFS
Sequence in context: A352200 A066182 A195114 * A194984 A194988 A195074
KEYWORD
nonn,easy
AUTHOR
Robert G. Wilson v, Jan 29 2001
STATUS
approved