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%I #23 Nov 13 2019 16:06:24
%S 1,7,35,119,387,1050,2786,7160,17157,39087,78453,167183,344072,697116,
%T 1310344,2455274,4569557,7758203,13461761,23063807,39017035,66702580,
%U 106675941,172270944,274763136,437839603,693741098,1044076002,1596344378,2414009807,3653875720
%N Positions of 1 in A328018.
%C Does a(n+1)/a(n) tend to 1 as n tends to infinity? - _Rémy Sigrist_, Nov 11 2019
%H Rémy Sigrist, <a href="/A328019/b328019.txt">Table of n, a(n) for n = 1..10000</a>
%H Rémy Sigrist, <a href="/A328019/a328019.gp.txt">PARI program for A328019</a>
%F a(1) = 1; a(n + 1) = A092433(a(n)) for n > 0.
%e A328018 starts like this: 1, 2, 3, 4, 5, 6, 1, 8, 9, 10, 11, 12, 13, 2, 15, 16, 3, 18, 19, 20, 4, 22, 23, 24, 25, 26, 5, 6, 29, 30, 31, 32, 33, 34, 1, 36, 8, 38, 39, 40.
%e This has 1's in positions 1, 7 and 35. Therefore, 1, 7 and 35 are in the sequence.
%t With[{s = Select[Range[10^6], Or[Mod[#, 7] == 0, DigitCount[#, 10, 7] > 0] &]}, Nest[Append[#, s[[#[[-1]] ]] ] &, {1}, 12]] (* _Michael De Vlieger_, Oct 17 2019 *)
%o (PARI) print1 (w=1", "); k=0; for (n=1, oo, if (n%7==0 || setsearch(Set(digits(n)),7), if (w==k++, print1 (w=n", ")))) \\ _Rémy Sigrist_, Nov 11 2019
%o (PARI) See Links section.
%Y Cf. A092433, A328018.
%K nonn,base
%O 1,2
%A Rens Reus and _David A. Corneth_, Oct 01 2019
%E More terms from _Rémy Sigrist_, Nov 11 2019