Solutions for some Project Euler (http://projecteuler.net/index.php?section=problems) problems, in RPL+ and JavaScript.

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#1 Add all the natural numbers below one thousand that are multiples of 3 or 5.

#2 By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

#3 Find the largest prime factor of a composite number.

One-liner.

#5 What is the smallest number divisible by each of the numbers 1 to 20?

One-liner.

#6 What is the difference between the sum of the squares and the square of the sums?

One-liner.

#7 Find the 10001st prime.

One-liner.

#10 Calculate the sum of all the primes below two million.

One-liner.

#12 What is the value of the first triangle number to have over five hundred divisors?

#13 Find the first ten digits of the sum of one-hundred 50-digit numbers.

One-liner in GS/ME.

#14 Find the longest sequence using a starting number under one million.

#15 Starting in the top left corner in a 20 by 20 grid, how many routes are there to the bottom right corner?

One-liner.

#16 What is the sum of the digits of the number 2^1000?

#18 Find the maximum sum travelling from the top of the triangle to the base.

#20 Find the sum of digits in 100!

#24 What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9?

One-liner.

#25 What is the first term in the Fibonacci sequence to contain 1000 digits?

#29 How many distinct terms are in the sequence generated by a^b for 2 ≤ a ≤ 100 and 2 ≤ b ≤ 100?

#48 Find the last ten digits of 1^1 + 2^2 + ... + 1000^1000.

#67 Using an efficient algorithm find the maximal sum in the triangle?

One-liner in GS/ME.

#97 Find the last ten digits of the non-Mersenne prime: 28433 × 2^7830457 + 1.

One-liner.

#179 Consecutive positive divisors

[EDIT: this list is now outdated, as many more solutions have been added.]