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A154614
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Triangle read by rows where T(m,n)=mn+m+n-1, 1<=n<=m.
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1
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2, 4, 7, 6, 10, 14, 8, 13, 18, 23, 10, 16, 22, 28, 34, 12, 19, 26, 33, 40, 47, 14, 22, 30, 38, 46, 54, 62, 16, 25, 34, 43, 52, 61, 70, 79, 18, 28, 38, 48, 58, 68, 7, 88, 98, 20, 31, 42, 53, 64, 75, 86, 97, 108, 119
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| T(m,n)+2 = (n+1)*(m+1) is not prime.
T(m,m)=m^2+2m-1=(2, 7, 14, 23, 34, 47,...)and T(m,m)+2 is a square.
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EXAMPLE
| Triangle begins:
2;
4, 7;
6, 10, 14;
8, 13, 18, 23;
10, 16, 22, 28, 34;
12, 19, 26, 33, 40, 47;
14, 22, 30, 38, 46, 54, 62;
16, 25, 34, 43, 52, 61, 70, 79;
18, 28, 38, 48, 58, 68, 78, 88, 98;
20, 31, 42, 53, 64, 75, 86, 97, 108, 119;
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CROSSREFS
| Cf. A040976
Sequence in context: A129980 A198137 A126786 * A161211 A161368 A023978
Adjacent sequences: A154611 A154612 A154613 * A154615 A154616 A154617
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KEYWORD
| nonn,easy,tabl
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 16 2009
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