A180479 Numbers m such that m/k is an integer. m = (x_1 x_2 ... x_r) where x_i are digits of m, k = x_1*r + x_2*(r-1) + ... + x_r*1.
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16, 20, 24, 30, 32, 36, 40, 48, 50, 60, 64, 70, 80, 90, 96, 110, 112, 132, 170, 184, 220, 224, 225, 252, 264, 275, 312, 330, 336, 340, 342, 396, 414, 418, 440, 441, 448, 510, 550, 621, 624, 660, 665, 680, 684, 770, 812, 825, 828
Offset: 1
Examples
For m=132, r=3, 132/(1*3+3*2+2*1)=12, so m=132 belongs to the sequence.
Links
- Paolo P. Lava, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Select[Range[1000], Mod[#, Total[ IntegerDigits[#] Reverse@ Range@ IntegerLength@ #]] == 0 &] (* Giovanni Resta, Aug 18 2015 *)
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PARI
isok(n) = {my(d = digits(n)); ! (n % sum(kk=1, #d, d[kk]*(#d-kk+1)));} \\ Michel Marcus, Aug 18 2015
Comments