A359125 Largest prime factor of A359124(n).

2, 13, 31, 19, 6173, 123457, 154321, 333667, 333667, 3388877, 4281283, 2630197, 26798700427, 8663199947, 2523244037, 12873492085621702963, 32929947197382727, 17539959825403, 71595329159622797, 325339942922532262019, 9999103057380477280607, 17465868005034957301, 1423364280511

Offset: 1

Author

N. J. A. Sloane, Dec 20 2022

Keywords

• nonn
• base

Comments

Has the same relation to A359124 as A075032 does to A007908. Suggested by A069048.

Crossrefs

Cf. A007908, A069048, A075032, A359124.

Programs

Mathematica

FactorInteger[#][[-1,1]]&/@Table[FromDigits[Flatten[IntegerDigits/@Range[n]]]+1,{n,30}] (* Harvey P. Dale, Dec 20 2022 *)

Python

from sympy import factorint
def a(n): return max(factorint(int("".join(map(str, range(1, n+1)))) + 1))
print([a(n) for n in range(1, 24)]) # Michael S. Branicky, Dec 20 2022