A256884 Numbers divisible by prime(d+1) for each digit d of their base-4 representation.
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
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.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
Select[Range[0,2000],AllTrue[#/(Prime[#+1]&/@IntegerDigits[#,4]),IntegerQ]&] (* Harvey P. Dale, Mar 13 2025 *)
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PARI
is(n,b=4)=!for(i=1,#d=Set(digits(n,b)),n%prime(d[i]+1)&&return)
Comments