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A285098
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Row sums of irregular triangle A070168.
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3
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1, 3, 23, 7, 20, 29, 124, 15, 147, 30, 117, 41, 63, 138, 296, 31, 106, 165, 231, 50, 84, 139, 281, 65, 294, 89, 40616, 166, 212, 326, 40486, 63, 377, 140, 258, 201, 259, 269, 986, 90, 40589, 126, 588, 183, 253, 327, 40455, 113, 382, 344, 514, 141, 223, 40670, 41000, 222
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OFFSET
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1,2
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COMMENTS
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a(n) is the sum of numbers in trajectory of Terras-modified Collatz problem with first number n.
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LINKS
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Indranil Ghosh, Table of n, a(n) for n = 1..10000
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EXAMPLE
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The 5th row of irregular triangle A070168 is [5, 8, 4, 2, 1] whose sum is 20. a(5) = 5 + 8 + 4 + 2 + 1 = 20.
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MATHEMATICA
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a[n_]:=If[n<2, 1, If[OddQ[n], (3n + 1)/2, n/2]]; Table[-1 + Plus @@ FixedPointList[a, n], {n, 100}]
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PROG
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(Python)
def a(n):
if n==1: return 1
l=[n]
while True:
if n%2==0: n//=2
else: n = (3*n + 1)//2
l.append(n)
if n<2: break
return sum(l)
print([a(n) for n in range(1, 101)])
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CROSSREFS
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Cf. A033493, A070168.
Sequence in context: A105433 A196086 A196083 * A088605 A272816 A063562
Adjacent sequences: A285095 A285096 A285097 * A285099 A285100 A285101
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KEYWORD
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nonn
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AUTHOR
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Indranil Ghosh, Apr 17 2017
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STATUS
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approved
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