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A064423 Position of n-th prime in A064413 (if it begins at 2). 5
1, 4, 9, 13, 19, 27, 32, 36, 42, 56, 60, 66, 73, 80, 88, 99, 106, 114, 127, 133, 137, 150, 159, 166, 181, 188, 196, 202, 206, 215, 235, 252, 258, 263, 278, 286, 296, 304, 313, 327, 335, 343, 362, 370, 376, 380, 400, 419, 429, 437, 443, 457, 461, 473, 486, 500, 509, 516, 529, 539, 548, 556, 580, 586, 598, 605, 628, 638, 654, 663, 669, 680, 698, 706, 723, 729, 735, 755, 765, 780, 797, 801, 813, 818, 832, 847, 856, 873, 881, 888, 897, 910, 926, 941, 952, 960, 970, 996, 1003, 1028, 1040, 1058, 1071, 1079, 1086, 1098, 1117, 1134, 1141, 1149, 1155, 1174, 1180, 1189, 1202, 1222, 1231, 1241, 1248, 1257, 1265, 1286, 1297, 1305, 1323, 1349, 1356, 1377, 1390, 1397, 1409, 1424, 1432, 1441, 1455, 1469, 1477, 1503, 1515, 1541, 1545, 1563, 1567, 1577, 1585, 1609, 1625, 1637, 1645, 1651, 1679, 1685, 1692, 1701, 1733, 1738, 1759 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

It can be shown that this sequence is monotonic.

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

J. C. Lagarias, E. M. Rains and N. J. A. Sloane, The EKG sequence, arXiv:math/0204011 [math.NT], 2002.

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

MATHEMATICA

terms = 100;

ekg[s_] := Block[{m = s[[-1]], k = 3}, While[MemberQ[s, k] || GCD[m, k] == 1, k++]; Append[s, k]];

EKG = Nest[ekg, {2, 4}, 12 terms];

a[n_] := FirstPosition[EKG, Prime[n]][[1]];

Array[a, terms] (* Jean-Fran├žois Alcover, Sep 02 2018, after Robert G. Wilson v in A064413 *)

CROSSREFS

Cf. A064413, A064425. See A064955 for better version.

Sequence in context: A312980 A035104 A141224 * A312981 A312982 A312983

Adjacent sequences:  A064420 A064421 A064422 * A064424 A064425 A064426

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane, Sep 30 2001

EXTENSIONS

More terms from Vladeta Jovovic, Oct 01 2001

STATUS

approved

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Last modified July 24 17:43 EDT 2021. Contains 346273 sequences. (Running on oeis4.)