Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="foo-1"></div>
<div class="foo-2"></div>
<div class="foo-3"></div>
<div class="foo-4"></div>
<div class="foo-5"></div>
<div class="foo-6"></div>

SassMeister-input.scss

// ----
// Sass (v3.4.13)
// Compass (v1.0.3)
// ----

div {
  display: inline-block;
  height: 100px;
  width: 100px;
}

$color-a: #018b37;
$color-b: #e47e7c;
$segments: 6;

$hue: hue($color-a) - hue($color-b);
$saturation: saturation($color-a) - saturation($color-b);
$lightness: lightness($color-a) - lightness($color-b);

$previous-color: $color-a;

@for $i from 1 through $segments {
  .foo-#{$i} {
    @if ($i == 1) {
      background-color: $color-a;
    }
    @else if ($i == $segments) {
      background-color: $color-b;
    }
    @else {
      $function-saturation: if($saturation > 0, 'desaturate', 'saturate');
      $function-lightness: if($lightness > 0, 'darken', 'lighten');
      
      $divisor: $segments - 2;
      $multiplier: $i - 1;
      
      $hueMod: adjust_hue($color-a, ($hue/$divisor) * $multiplier);
      $saturateMod: call($function-saturation, $hueMod, abs(($saturation/$divisor) * $multiplier));
      $lightnessMod: call($function-lightness, $saturateMod, abs(($lightness/$divisor) * $multiplier));
      
      background-color: $lightnessMod;
    }
  }
}

SassMeister-output.css

div {
  display: inline-block;
  height: 100px;
  width: 100px;
}

.foo-1 {
  background-color: #018b37;
}

.foo-2 {
  background-color: #09b8b5;
}

.foo-3 {
  background-color: #166be0;
}

.foo-4 {
  background-color: #6247e4;
}

.foo-5 {
  background-color: #cb7ce4;
}

.foo-6 {
  background-color: #e47e7c;
}

SassMeister-rendered.html

<div class="foo-1"></div>
<div class="foo-2"></div>
<div class="foo-3"></div>
<div class="foo-4"></div>
<div class="foo-5"></div>
<div class="foo-6"></div>