A309003 Carmichael numbers divisible by the sum of their prime factors, sopfr (A001414).

3240392401, 13577445505, 14446721521, 84127131361, 203340265921, 241420757761, 334797586201, 381334973041, 461912170321, 1838314142785, 3636869821201, 10285271821441, 17624045440981, 18773053896961, 20137015596061, 24811804945201, 26863480687681, 35598629998801

Offset: 1

Author

David James Sycamore, Jul 05 2019

Keywords

• nonn

Comments

Intersection of A002997 and A308643.

Intersection of A002997 and A036844.

Examples

			3240392401 = 29*37*41*73*1009, A001414(3240392401)=1189 = 29*41.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (calculated using data from Claude Goutier)
• Claude Goutier, Compressed text file carm10e22.gz containing all the Carmichael numbers up to 10^22.
• Index entries for sequences related to Carmichael numbers.

Crossrefs

Cf. A002997, A001414, A036844, A046347, A308643.

Programs

PARI

sopfr(f) = f[, 1]~*f[, 2];
isCarmichael(n, f)= bittest(n, 0) && !for(i=1, #f~, (f[i, 2]==1 && n%(f[i, 1]-1)==1)||return) && (#f~>1);
isok(n) = my(f=factor(n)); isCarmichael(n, f) && !(n % sopfr(f)); \\ Michel Marcus, Jul 07 2019