A296117 Base-2 pseudoprimes of the form 2*p*q where p and q are primes.

161038, 49699666, 760569694, 4338249646, 357647681422, 547551530002, 3299605275646, 22999986587854, 42820164121582, 55173914702146, 69345154539266, 353190859033982, 24119706662444014, 48598788448239058, 55178647709248306, 69971112304474978, 75261329778536926, 109621774031447966, 159505024396922926, 182794471667739518, 521658362398657186, 932684895710578126

Offset

1,1

Comments

a(5) and a(10) are found by McDaniel (1989). a(2)-a(4) are found by Rotkiewicz and Ziemak (1995).

Terms in this sequence are of the form 2pq where p and q are distinct odd primes (A075819). - Charles R Greathouse IV, Dec 05 2017

Links

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

W. L. McDaniel, Some pseudoprimes and related numbers having special forms, Math. Comp. 53:187 (1989), 407-409.

A. Rotkiewicz and K. Ziemak, On even pseudoprimes. The Fibonacci Quarterly 33:2 (1995), 123-125. doi:10.1080/00150517.1995.12429152

Prog

(PARI) list(lim)=my(v=List(), pq); forprime(p=3, lim\6, forprime(q=3, min(lim\(2*p), p), pq=p*q; if(Mod(4, pq)^pq==2, listput(v, 2*pq)))); Set(v) \\ Charles R Greathouse IV, Dec 05 2017

Crossrefs

Subsequence of A006935 and hence of A015919.

The even terms of A215672.

Intersection of A006935 and A215672. - Felix Fröhlich, Dec 05 2017

Cf. A270973, A075819, A001220.

Sequence in context: A108162 A270973 A287297 * A176770 A038681 A339676

Adjacent sequences: A296114 A296115 A296116 * A296118 A296119 A296120

Keyword

nonn

Author

Max Alekseyev, Dec 05 2017

Extensions

a(13)-a(22) added by Max Alekseyev, Feb 19 2026

Status

approved