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A154684
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Triangle read by rows where T(m,n)=2mn+m+n-3, 1<=n<=m.
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2
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1, 4, 9, 7, 14, 21, 10, 19, 28, 37, 13, 24, 35, 46, 57, 16, 29, 42, 55, 68, 81, 19, 34, 49, 64, 79, 94, 109, 22, 39, 56, 73, 90, 107, 124, 141, 25, 44, 63, 82, 101, 120, 139, 158, 177, 28, 49, 70, 91, 112, 133, 154, 175, 196, 217
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| 2*T(m,n)+7 = (2n+1)*(2m+1) is not prime
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EXAMPLE
| Triangle begins:
1;
4, 9;
7, 14, 21;
10, 19, 28, 37;
13, 24, 35, 46, 57;
16, 29, 42, 55, 68, 81;
19, 34, 49, 64, 79, 94, 109;
22, 39, 56, 73, 90, 107, 124, 141;
25, 44, 63, 82, 101, 120, 139, 158, 177;
28, 49, 70, 91, 112, 133, 154, 175, 196, 217;
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CROSSREFS
| Cf. A153053, A105760, A162265 (row sums).
Sequence in context: A155787 A179222 A123157 * A096982 A205297 A159643
Adjacent sequences: A154681 A154682 A154683 * A154685 A154686 A154687
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KEYWORD
| nonn,tabl,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 18 2009
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