

A236246


Indices n for which A229037(n)=1.


3



1, 2, 4, 5, 10, 11, 13, 14, 28, 29, 31, 32, 37, 38, 40, 41, 82, 83, 85, 86, 92, 93, 96, 105, 111, 112, 115, 116, 122, 177, 236, 237, 244, 245, 247, 266, 267, 270, 276, 277, 283, 294, 301, 302, 347, 558, 628, 638, 646, 647, 649, 655, 669, 674, 685, 686
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OFFSET

1,2


COMMENTS

Significant jumps occur at a(3)=4=2*a(2), a(5)=10=2*a(4), a(9)=28=2*a(8), a(17)=82=2*a(16), a(31)=236 >> a(29)=122, a(47)=628 >> a(44)=302, a(70)=1622 >> a(66)=809, a(90)=4165 >> a(87)=2062, ... . Here, the size of the terms roughly doubles over the interval of very few indices. The indices such that a(n[k]) >= 2*a(n[k1]) are n[k] = 3, 5, 9, 17, 30, 46, 69, 89, ... .
This sequence first differs from A003278 at the 21st term, which is 92 here but 91 in A003278. Up to 91, each natural number n that did not appear in this sequence failed to do so because there were two smaller numbers na and n2a, with A229037(na) and A229037(n2a) both equal to 1. 91 is missing from this sequence; in other words, A229037(91) is not 1, because A229037(27) = 9 and A229037(59) = 5.  Jack W Grahl, Dec 28 2014


LINKS



PROG

(Haskell)
a236246 n = a236246_list !! (n1)
a236246_list = filter ((== 1) . a229037) [1..]
(Python)
for n in range(10**6):
....i, j, b = 1, 1, set()
....while n2*i >= 0:
........i += 1
........while j in b:
............b.remove(j)
............j += 1
....if j == 1:


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



