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.

A256884 Numbers divisible by prime(d+1) for each digit d of their base-4 representation.

Original entry on oeis.org

0, 10, 21, 40, 63, 84, 90, 105, 130, 140, 150, 160, 165, 170, 175, 210, 252, 276, 324, 330, 336, 345, 360, 390, 405, 420, 520, 560, 600, 630, 640, 650, 660, 680, 700, 735, 770, 840, 861, 910, 1008, 1044, 1050, 1092, 1104, 1110, 1170, 1260, 1284, 1290, 1296, 1320, 1344, 1350, 1365, 1380, 1407, 1410, 1440, 1470, 1533, 1560, 1620
Offset: 1

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Author

M. F. Hasler, Apr 11 2015

Keywords

Comments

The base-4 variant of A256882, A256883, A256865, ..., A256870 in bases 2, ..., 10.
A variant of A256874 where digits 0 are forbidden and divisibility by prime(d) is required.

Examples

			0 is divisible by prime(0+1)=2.
10 = 22_4 and is divisible by prime(2+1)=5.
n = 1, 2, 3 are not divisible by prime(n+1) = 3, 5, 7; nor are 4=10_4, 5=11_4, and 7=13_4 divisible by prime(1+1) = 3; nor are 6=12_4, 8=20_4, 9=21_4 divisible by prime(2+1)=5.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[0,2000],AllTrue[#/(Prime[#+1]&/@IntegerDigits[#,4]),IntegerQ]&] (* Harvey P. Dale, Mar 13 2025 *)
  • PARI
    is(n,b=4)=!for(i=1,#d=Set(digits(n,b)),n%prime(d[i]+1)&&return)