Increasing gaps between consecutive Niven numbers: Difference between revisions

=={{header|Go}}==

This reuses code from the [[https://rosettacode.org/wiki/Harshad_or_Niven_series#Go Harshad or Niven series]] task though converted to use 'uint64' rather than 'int' in case anyone is running Go on a 32-bit platform.

<lang go>package main

import "fmt"

type is func() uint64

func newSum() is {

var ms is

ms = func() uint64 {

ms = newSum()

return ms()

}

var msd, d uint64

return func() uint64 {

if d < 9 {

d++

} else {

d = 0

msd = ms()

}

return msd + d

}

}

func newHarshard() is {

i := uint64(0)

sum := newSum()

return func() uint64 {

for i++; i%sum() != 0; i++ {

}

return i

}

}

func commatize(n uint64) string {

s := fmt.Sprintf("%d", n)

le := len(s)

for i := le - 3; i >= 1; i -= 3 {

s = s[0:i] + "," + s[i:]

}

return s

}

func main() {

fmt.Println("Gap Index of gap Starting Niven")

fmt.Println("=== ============= ==============")

h := newHarshard()

pg := uint64(0) // previous highest gap

pn := h() // previous Niven number

for i, n := uint64(1), h(); n <= 20e9; i, n = i+1, h() {

g := n - pn

if g > pg {

fmt.Printf("%3d %13s %14s\n", g, commatize(i), commatize(pn))

pg = g

}

pn = n

}

}</lang>

{{out}}

<pre>

Gap Index of gap Starting Niven

=== ============= ==============

1 1 1

2 10 10

6 11 12

7 26 63

8 28 72

10 32 90

12 83 288

14 102 378

18 143 558

23 561 2,889

32 716 3,784

36 1,118 6,480

44 2,948 19,872

45 4,194 28,971

54 5,439 38,772

60 33,494 297,864

66 51,544 478,764

72 61,588 589,860

88 94,748 989,867

90 265,336 2,879,865

99 800,054 9,898,956

108 3,750,017 49,989,744

126 6,292,149 88,996,914

135 44,194,186 689,988,915

144 55,065,654 879,987,906

150 61,074,615 989,888,823

153 179,838,772 2,998,895,823

192 399,977,785 6,998,899,824

201 497,993,710 8,889,999,624

234 502,602,764 8,988,988,866

258 547,594,831 9,879,997,824

276 1,039,028,518 18,879,988,824

</pre>