A182087 Carmichael numbers of the form C = (30n-p)*(60n-(2p+1))*(90n-(3p+2)), where n is a natural number and p, 2p+1, 3p+2 are all three prime numbers.
1729, 172081, 294409, 1773289, 4463641, 56052361, 118901521, 172947529, 216821881, 228842209, 295643089, 798770161, 1150270849, 1299963601, 1504651681, 1976295241, 2301745249, 9624742921, 11346205609, 13079177569
Offset: 1
Keywords
Links
- Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
- Eric Weisstein's World of Mathematics, Carmichael Number.
Programs
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PARI
list(lim)={ my(v=List(),f); for(k=1,round(solve(x=(lim/162000)^(1/3),lim^(1/3),(30*x-23)*(60*x-47)*(90*x-71)-lim)), n=(30*k-23)*(60*k-47)*(90*k-71)-1; f=factor(30*k-23); for(i=1,#f[,1],if(f[i,2]>1 || n%(f[i,1]-1), next(2))); f=factor(60*k-47); for(i=1,#f[,1],if(f[i,2]>1 || n%(f[i,1]-1), next(2))); f=factor(90*k-71); for(i=1,#f[,1],if(f[i,2]>1 || n%(f[i,1]-1), next(2))); listput(v,n+1) ); for(k=2,round(solve(x=(lim/162000)^(1/3),lim^(1/3),(30*x-29)*(60*x-59)*(90*x-89)-lim)), n=(30*k-29)*(60*k-59)*(90*k-89)-1; f=factor(30*k-29); for(i=1,#f[,1],if(f[i,2]>1 || n%(f[i,1]-1), next(2))); f=factor(60*k-59); for(i=1,#f[,1],if(f[i,2]>1 || n%(f[i,1]-1), next(2))); f=factor(90*k-89); for(i=1,#f[,1],if(f[i,2]>1 || n%(f[i,1]-1), next(2))); listput(v,n+1) ); vecsort(Vec(v)) }; \\ Charles R Greathouse IV, Oct 02 2012
Comments