cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A333703 Numbers k such that k divides the sum of digits in primorial base of all numbers from 1 to k.

Original entry on oeis.org

1, 2, 10, 22, 58, 62, 63, 64, 66, 67, 68, 118, 178, 418, 838, 1258, 1264, 1265, 1277, 1278, 1678, 2098, 4618, 9238, 10508, 10509, 10510, 10512, 10513, 10514, 13858, 14704, 14754, 18478, 23098, 23102, 23276, 27718, 60058, 120118, 138602, 139016, 139024, 139134
Offset: 1

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Author

Amiram Eldar, Apr 02 2020

Keywords

Comments

The corresponding quotients are 1, 1, 2, 3, 4, 4, 4, 4, 4, ....

Examples

			10 is a term since the sum of digits in primorial base (A276150) of k from 1 to 10 is 1 + 1 + 2 + 2 + 3 + 1 + 2 + 2 + 3 + 3 = 20, which is divisible by 10.
		

Crossrefs

Programs

  • Mathematica
    max = 10; bases = Prime@Range[max, 1, -1]; nmax = Times @@ bases - 1; s[n_] := Plus @@ IntegerDigits[n, MixedRadix[bases]]; seq = {}; sum = 0; Do[sum += s[n]; If[Divisible[sum, n], AppendTo[seq, n]], {n, 1, 10^6}]; seq