lychrel

test for Lychrel numbers

v1.0.1

isPalindrome(val)

Checks if a number/string is a palindrome

• @param {String/Number} val
• @return {Boolean}

import {isPalindrome} from 'lychrel';
 
isPalindrome(123321);  // true
isPalindrome('otto');  // true
isPalindrome(123);  // false

reverseAndAdd(val)

Reverses the digits in a number and adds it to the original

• @param {Number} val
• @return {Number}

import {reverseAndAdd} from 'lychrel';
 
reverseAndAdd(14);  // 55
reverseAndAdd(123);  // 444

isLychrel(val, maxIterations)

Attempts to determine if a number is a Lychrel number. Quits after max iterations.

• @param {Number} val
• @param {Number} [maxIterations = 100]
• @return {Object}
  • {Boolean/undefined} isLychrel - false if disproven, undefined if indeterminate before max iterations
  • {Number} lastValue - last calculated value
  • {Number} iterations

import {isLychrel} from 'lychrel';
 
isLychrel(89);
// {
//   isLychrel: false,
//   lastValue: 8813200023188,
//   iterations: 24,
// }
 
isLychrel(196);
// {
//   isLychrel: undefined,
//   lastValue: 820255645655561900,
//   iterations: 100,
// }
 
isLychrel(196, 200);
// {
//   isLychrel: undefined,
//   lastValue: 3417785356534986000,
//   iterations: 200,
// }

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