A064955 Position of n-th prime in A064413.

2, 5, 10, 14, 20, 28, 33, 37, 43, 57, 61, 67, 74, 81, 89, 100, 107, 115, 128, 134, 138, 151, 160, 167, 182, 189, 197, 203, 207, 216, 236, 253, 259, 264, 279, 287, 297, 305, 314, 328, 336, 344, 363, 371, 377, 381, 401, 420, 430, 438, 444, 458, 462, 474, 487, 501, 510, 517, 530, 540, 549, 557, 581, 587, 599, 606, 629, 639, 655, 664, 670, 681, 699, 707, 724, 730, 736, 756, 766, 781, 798, 802, 814, 819, 833, 848, 857, 874, 882, 889, 898, 911, 927, 942, 953, 961, 971, 997, 1004, 1029, 1041, 1059, 1072, 1080, 1087, 1099, 1118, 1135, 1142, 1150, 1156, 1175, 1181, 1190, 1203, 1223, 1232, 1242, 1249, 1258, 1266, 1287, 1298, 1306, 1324, 1350, 1357, 1378, 1391, 1398, 1410, 1425, 1433, 1442, 1456, 1470, 1478, 1504, 1516, 1542, 1546, 1564, 1568, 1578, 1586, 1610, 1626, 1638, 1646, 1652, 1680, 1686, 1693, 1702, 1734, 1739, 1760

Offset

1,1

Comments

It can be shown that this sequence is monotonic.

A073734(a(n)) = A000040(n) for n > 1. [Reinhard Zumkeller, Sep 17 2001]

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, Exper. Math. 11 (2002), 437-446.

Index entries for sequences related to EKG sequence

Formula

a(n) = A064664(p(n)).

Mathematica

ekg[s_] := Block[{m = s[[-1]], k = 3}, While[MemberQ[s, k] || GCD[m, k] == 1, k++]; Append[s, k]];
A064413 = Nest[ekg, {1, 2}, 1000];
Position[A064413, _?PrimeQ] // Flatten (* Jean-François Alcover, Nov 03 2018, after Robert G. Wilson v in 064413 *)

Prog

(Haskell)
import Data.List (elemIndex)
import Data.Maybe (fromJust)
a064955 n = a064955_list !! (n-1)
a064955_list =
   map ((+ 1) . fromJust . (`elemIndex` a064413_list)) a000040_list
-- Reinhard Zumkeller, Sep 17 2001

Crossrefs

Cf. A064413, A064425.

Sequence in context: A115757 A159032 A082745 * A352189 A101725 A274453

Adjacent sequences: A064952 A064953 A064954 * A064956 A064957 A064958

Keyword

nonn

Author

N. J. A. Sloane, Oct 30 2001

Status

approved