A005108 - OEIS

A005108

Class 4+ primes (for definition see A005105).
(Formerly M5350)

73, 313, 443, 617, 661, 673, 677, 691, 739, 757, 823, 887, 907, 941, 977, 1093, 1109, 1129, 1201, 1213, 1303, 1361, 1447, 1453, 1543, 1553, 1621, 1627, 1657, 1753, 1811, 1867, 1873, 1993, 1997, 2017, 2081, 2083, 2113, 2269, 2273, 2281, 2293, 2333, 2341

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, A18.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

T. D. Noe, Table of n, a(n) for n=1..10000

MAPLE

For Maple program see Mathar link in A005105.

MATHEMATICA

PrimeFactors[n_Integer] := Flatten[ Table[ #[[1]], {1}] & /@ FactorInteger[n]]; f[n_Integer] := Block[{m = n}, If[m == 0, m = 1, While[ IntegerQ[m/2], m /= 2]; While[ IntegerQ[m/3], m /= 3]]; Apply[Times, PrimeFactors[m] + 1]]; ClassPlusNbr[n_] := Length[ NestWhileList[f, n, UnsameQ, All]] - 3; Prime[ Select[ Range[350], ClassPlusNbr[ Prime[ # ]] == 4 &]]

CROSSREFS

Cf. A005113, A005105, A005106, A005107.

Sequence in context: A158744 A297430 A142406 * A142810 A142279 A092342

Adjacent sequences: A005105 A005106 A005107 * A005109 A005110 A005111

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Simon Plouffe

EXTENSIONS

Edited and extended by Robert G. Wilson v, Mar 20 2003

STATUS

approved