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A372292
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Numbers that occur more than once in the odd bisection of A371094.
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4
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21, 117, 213, 309, 341, 405, 501, 597, 693, 789, 885, 981, 1077, 1173, 1269, 1365, 1461, 1557, 1653, 1749, 1845, 1877, 1941, 2037, 2133, 2229, 2325, 2421, 2517, 2613, 2709, 2805, 2901, 2997, 3093, 3189, 3285, 3381, 3413, 3477, 3573, 3669, 3765, 3861, 3957, 4053, 4149, 4245, 4341, 4437, 4533, 4629, 4725, 4821, 4917
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OFFSET
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1,1
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COMMENTS
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Numbers that occur more than once in array A371100.
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LINKS
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EXAMPLE
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PROG
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(PARI)
A371094(n) = { my(m=1+3*n, e=valuation(m, 2)); ((m*(2^e)) + (((4^e)-1)/3)); };
isA372292(n) = if(!(n%2), 0, my(c=0); forstep(k=1, n, 2, if(A371094(k)==n, c++)); (c>1));
(PARI)
search_up_to = 1398101;
A371094(n) = { my(m=1+3*n, e=valuation(m, 2)); ((m*(2^e)) + (((4^e)-1)/3)); };
A372292list(up_to_n) = { my(v=vector((1+up_to_n)/2), x, lista=List([])); forstep(k=1, up_to_n, 2, x=A371094(k); if(x <= up_to_n, v[(x+1)/2]++)); for(i=1, (1+up_to_n)/2, if(v[i]>1, listput(lista, i+i-1))); Vec(lista); };
v372292 = A372292list(search_up_to);
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CROSSREFS
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KEYWORD
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nonn,new
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AUTHOR
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STATUS
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approved
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