generate-list-blob.js

const unix = Math.round(+new Date()/1000)
const rippleEpoch = 946684800
const lifetime = 31536000 // seconds from now 

const list = {
  sequence: 1,
  expiration: unix + lifetime - rippleEpoch,
  validators: [
    {
      validation_public_key: '03d9aef2401781987d12cf099a2e3750eb290cd2afb9a0519a0567a00705edd3d3'
    },
    {
      validation_public_key: '03606c76a41ca7248312388d7e958b1ff48445e0f498a71ada905aa4f9fcbf6d5e'
    },
    {
      validation_public_key: '03280b1651dd14f4a56d834acbe6637645032d871d0bdff3ec0b8335a021eec6c2'
    },
    {
      validation_public_key: '02acaa0a6ab8c6bad6495df58c1a5adb9bc3054304743deea5f68b6b5560ccd15e'
    },
    {
      validation_public_key: '031326e0c6709b98d33fec3d5a626a6430c76281364227b07f732afe70668360ac'
    }
  ]
}

var blob_buf = Buffer.from(JSON.stringify(list));

console.log(blob_buf.toString('base64'))