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A180471 Irregular triangle in which row n has all primes q such that prime(n)*q is a base-2 Fermat pseudoprime. 4
31, 257, 73, 89, 683, 113, 11, 151, 331, 73, 109, 61681, 127, 337, 5419, 178481, 2796203, 157, 1613, 233, 1103, 2089, 3033169, 1321, 20857, 599479, 281, 86171, 122921, 19, 37, 109, 433, 38737, 2731, 8191, 121369, 22366891, 13367, 164511353, 8831418697, 23, 353, 397, 683, 2113, 2931542417 (list; graph; refs; listen; history; text; internal format)
OFFSET

5,1

COMMENTS

The length of row n is A085014(n). The smallest and largest primes in row n are A085012(n) and A085019(n).

REFERENCES

See A085012.

LINKS

Table of n, a(n) for n=5..51.

Index entries for sequences related to pseudoprimes

EXAMPLE

The irregular triangle begins

31

none

257

73

89, 683

113

11, 151, 331

73, 109

61681

MATHEMATICA

Flatten[Table[p=Prime[n]; q=Transpose[FactorInteger[2^(p-1)-1]][[1]]; cnt={}; Do[If[PowerMod[2, p*q[[i]]-1, p*q[[i]]]==1, AppendTo[cnt, q[[i]]]], {i, Length[q]}]; cnt, {n, 5, 50}]]

CROSSREFS

Sequence in context: A042872 A142623 A089705 * A125368 A126526 A008386

Adjacent sequences:  A180468 A180469 A180470 * A180472 A180473 A180474

KEYWORD

nonn,tabf

AUTHOR

T. D. Noe, Jan 19 2011

STATUS

approved

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Last modified March 18 13:47 EDT 2019. Contains 321289 sequences. (Running on oeis4.)