A216994 Multiples of 7 such that the digit sum is divisible by 7.

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

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