login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A081639 Class 11+ primes. 15
8524807, 18381361, 18575041, 19180817, 21312019, 31984321, 34099231, 40357021, 44206633, 44839273, 48499459, 51148847, 51444961, 51884467, 54144121, 57129613, 57780487, 58293601, 61378571, 65578901, 66786721, 66787873 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

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

LINKS

Table of n, a(n) for n=1..22.

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[150000], ClassPlusNbr[ Prime[ # ]] == 11 &]]

CROSSREFS

Cf. A005113, A005105 - A005108, A081633 - A081638, A084071, A090468.

Sequence in context: A205179 A251173 A203824 * A141137 A184150 A236450

Adjacent sequences:  A081636 A081637 A081638 * A081640 A081641 A081642

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Mar 20 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 22 08:25 EDT 2019. Contains 322329 sequences. (Running on oeis4.)