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Search: id:A099627
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| A099627 |
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Triangle T(n,k)=2^n+2^k-1 with n>=k>=0. |
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+0
7
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| 1, 2, 3, 4, 5, 7, 8, 9, 11, 15, 16, 17, 19, 23, 31, 32, 33, 35, 39, 47, 63, 64, 65, 67, 71, 79, 95, 127, 128, 129, 131, 135, 143, 159, 191, 255, 256, 257, 259, 263, 271, 287, 319, 383, 511, 512, 513, 515, 519, 527, 543, 575, 639, 767, 1023, 1024, 1025, 1027, 1031, 1039
(list; table; graph; listen)
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OFFSET
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0,2
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COMMENT
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Positive integers m where m-th Catalan number A000108(m)=C(2m,m)/(m+1) is not divisible by 4, i.e. where A048881(m) is 0 or 1.
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FORMULA
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As sequence, a(n)=A048645(n+2)-1.
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EXAMPLE
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Rows start 1; 2,3; 4,5,7; 8,9,11,15; 16,17,19,23,31; 32,33,35,39,47,63; etc. T(5,3)=2^5+2^3-1=32+8-1=39.
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CROSSREFS
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Numbers in A000225 or A099628.
Sequence in context: A087797 A153730 A140691 this_sequence A138039 A080664 A098776
Adjacent sequences: A099624 A099625 A099626 this_sequence A099628 A099629 A099630
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KEYWORD
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easy,nonn,tabl
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), Oct 25 2004
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