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
Keywords
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
Programs
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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
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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 *)
Comments