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Positions of even terms in A004001.
3

%I #7 Mar 19 2017 01:09:55

%S 3,4,6,7,8,10,13,14,15,16,18,20,21,23,24,28,29,30,31,32,34,36,39,41,

%T 42,44,45,49,52,53,54,59,60,61,62,63,64,66,68,70,71,73,75,76,78,81,84,

%U 85,86,88,91,94,95,96,98,99,103,104,105,106,108,109,113,114,115,116,122,123,124,125,126,127,128,130,132,134,137,139,141,142,144

%N Positions of even terms in A004001.

%H Antti Karttunen, <a href="/A283482/b283482.txt">Table of n, a(n) for n = 1..8264</a>

%t a[n_] := a[n] = If[n <= 2, 1, a[a[n - 1]] + a[n - a[n - 1]]]; Select[Range@ 144, EvenQ@ a[#] &] (* _Michael De Vlieger_, Mar 18 2017, after _Robert G. Wilson v_ at A004001 *)

%o (Scheme, with _Antti Karttunen_'s IntSeq-library)

%o (define A283482 (ZERO-POS 1 1 A095901))

%Y Cf. A283481 (complement), A283471 (a subsequence).

%Y Positions of zeros in A095901.

%Y Cf. A004001.

%K nonn

%O 1,1

%A _Antti Karttunen_, Mar 18 2017