A217002 Lucas-Carmichael numbers with 6 prime factors.

139501439, 196377335, 206238815, 239875559, 287432495, 336545495, 353107799, 381626399, 394426655, 406335215, 461829599, 464972255, 577901519, 592557119, 649351295, 653067359, 674628479, 761212655, 775931519, 777724415, 929892095, 993625919, 1073352959

Offset

1,1

Links

Daniel Suteu, Table of n, a(n) for n = 1..9382 (first 1000 terms from Donovan Johnson)

Example

A006972(385) = 139501439 = 7*11*17*19*71*79.

Prog

(PARI) upto(n, k=6) = my(A=vecprod(primes(k+1))\2, B=n); (f(m, l, p, k, u=0, v=0) = my(list=List()); if(k==1, forprime(p=u, v, my(t=m*p); if((t+1)%l == 0 && (t+1)%(p+1) == 0, listput(list, t))), forprime(q = p, sqrtnint(B\m, k), my(t = m*q); my(L=lcm(l, q+1)); if(gcd(L, t) == 1, my(u=ceil(A/t), v=B\t); if(u <= v, my(r=nextprime(q+1)); if(k==2 && r>u, u=r); list=concat(list, f(t, L, r, k-1, u, v)))))); list); vecsort(Vec(f(1, 1, 3, k))); \\ Daniel Suteu, Sep 03 2022

Crossrefs

Cf. A006972 (Lucas-Carmichael numbers), A216925, A216926, A216927, A217003, A217091.

Sequence in context: A251505 A034642 A109093 * A036744 A257643 A262532

Adjacent sequences: A216999 A217000 A217001 * A217003 A217004 A217005

Keyword

nonn

Author

Donovan Johnson, Sep 22 2012

Status

approved