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

1,1

Comments

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

Links

Table of n, a(n) for n=1..23.

Mathematica

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

Prog

(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

Crossrefs

Cf. A007908, A069048, A075032, A359124.

Sequence in context: A300111 A030452 A132602 * A001914 A254447 A031392

Adjacent sequences: A359122 A359123 A359124 * A359126 A359127 A359128

Keyword

nonn,base

Author

N. J. A. Sloane, Dec 20 2022

Status

approved