A168338 Sum of the largest digit of the divisors of n.

1, 3, 4, 7, 6, 12, 8, 15, 13, 9, 2, 18, 4, 14, 14, 21, 8, 29, 10, 15, 13, 6, 4, 30, 11, 12, 20, 26, 10, 26, 4, 24, 8, 14, 18, 41, 8, 20, 16, 27, 5, 29, 5, 14, 28, 12, 8, 44, 17, 19, 16, 21, 6, 41, 12, 40, 20, 20, 10, 40, 7, 12, 28, 30, 15, 24, 8, 26, 16, 32, 8, 60, 8, 17, 26, 31, 16, 38

Offset

1,2

References

J. Earls, "Black Hole 14," Mathematical Bliss, Pleroma Publications, 2009, pages 18-22. ASIN: B002ACVZ6O

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Example

a(16)=21 because the divisors of 16 are [1, 2, 4, 8, 16] and 1+2+4+8+6 = 21.

Mathematica

A168338[n_] := Total[Map[Max[IntegerDigits[#]] &, Divisors[n]]];
Array[A168338, 100] (* Paolo Xausa, May 03 2024 *)

Prog

(PARI) a(n)=sumdiv(n, d, vecmax(eval(Vec(Str(d))))) \\ Charles R Greathouse IV, May 22 2012

Crossrefs

Cf. A027750.

Sequence in context: A093811 A088000 A284344 * A034690 A069192 A076887

Adjacent sequences: A168335 A168336 A168337 * A168339 A168340 A168341

Keyword

base,easy,nonn,changed

Author

Jason Earls, Nov 23 2009

Status

approved