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A216994 Multiples of 7 such that the digit sum is divisible by 7. 8
7, 70, 77, 133, 266, 322, 329, 392, 399, 455, 511, 518, 581, 588, 644, 700, 707, 770, 777, 833, 966, 1015, 1085, 1141, 1148, 1204, 1274, 1330, 1337, 1463, 1526, 1596, 1652, 1659, 1715, 1785, 1841, 1848, 1904, 1974, 2023, 2093, 2156, 2212, 2219, 2282, 2289 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: Every century has a representation in the sequence.

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

1085 = 7*155 and 1 + 0 + 8 + 5 = 14 = 7*2.

MATHEMATICA

Select[7*Range[400], Mod[Total[IntegerDigits[#]], 7] == 0 &] (* T. D. Noe, Sep 24 2012 *)

PROG

(JavaScript)

function sumarray(arr) {

t = 0;

for (i = 0; i < arr.length; i++) t += arr[i];

return t;

}

for(s = 7; s < 3000; s += 7) {

a = new Array();

x = s.toString();

for (j = 0; j < x.length; j++) a[j] = Number(x.charAt(j));

if (sumarray(a) % 7 == 0) document.write(s + ", ");

}

CROSSREFS

Cf. A216995, A216996, A216997, A216998, A217009.

Sequence in context: A217400 A077683 A082797 * A121027 A062901 A204094

Adjacent sequences:  A216991 A216992 A216993 * A216995 A216996 A216997

KEYWORD

nonn,base

AUTHOR

Jon Perry, Sep 22 2012

STATUS

approved

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Last modified April 29 11:38 EDT 2017. Contains 285604 sequences.