This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A338011 #10 Jul 08 2021 23:16:24 %S A338011 49,161,323,329,377,451,539,989,1081,1127,1189,1771,1819,1891,2009, %T A338011 2033,2047,2303,2737,2849,3059,3289,3619,3653,3689,3827,4181,4301, %U A338011 4577,4879,4949,5671,5777,6049,6479,6533,6601,6721,7061,7399,7471,7567,7931 %N A338011 Odd composite integers m such that A004187(m)^2 == 1 (mod m). %C A338011 For a, b integers, the generalized Lucas sequence is defined by the relation U(n+2)=a*U(n+1)-b*U(n) and U(0)=0, U(1)=1. %C A338011 This sequence satisfies the relation U(p)^2 == 1 for p prime and b=1,-1. %C A338011 The composite numbers with this property may be called weak generalized Lucas pseudoprimes of parameters a and b. %C A338011 The current sequence is defined for a=7 and b=1. %D A338011 D. Andrica, O. Bagdasar, Recurrent Sequences: Key Results, Applications and Problems. Springer (2020) %D A338011 D. Andrica, O. Bagdasar, On some new arithmetic properties of the generalized Lucas sequences, Mediterr. J. Math. (to appear, 2021) %H A338011 Dorin Andrica and Ovidiu Bagdasar, <a href="https://doi.org/10.3390/math9080838">On Generalized Lucas Pseudoprimality of Level k</a>, Mathematics (2021) Vol. 9, 838. %t A338011 Select[Range[3, 8000, 2], CompositeQ[#] && Divisible[ChebyshevU[#-1, 7/2]*ChebyshevU[#-1, 7/2] - 1, #] &] %Y A338011 Cf. A338007 (a=3, b=1), A338008 (a=4, b=1), A338009 (a=5, b=1), A338010 (a=6, b=1). %K A338011 nonn %O A338011 1,1 %A A338011 _Ovidiu Bagdasar_, Oct 06 2020