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74

The smallest squares containingk 74's :
7744 = 882,   7447441 = 27292,   7497481744 = 865882,
7174474747441 = 26785212,   7479774747747481 = 864856912.

74 is the sum of m squares for m = 2, 3, ..., 59.

742 = 5476, a zigzag square with different digits.

742 is the third square which is the sum of 7 fourth powers in just 2 ways :
      [1,2,2,2,5,7,7], [3,3,3,4,4,5,8].
742 is the first square which is the sum of 8 fourth powers in just 3 ways :
      [1,2,2,2,3,5,5,8], [1,2,4,4,5,5,6,7], [1,3,4,5,5,6,6,6].

747 = 12151280273024, 12 + 212 + 512 + 282 + 0272 + 302 + 22 + 42 = 742.
748 = 899194740203776, 8 + 9 + 919 + 4 + 740 + 20 + 3776 = 742.

10k + 74k + 98k + 142k are squares for k = 1,2,3 (182, 1882, 20522).

Komachi Fraction : 742 = 3104892/567.

Komachi equations:
742 = 123 * 45 + 6 + 7 - 8 * 9 = 123 * 45 + 6 - 7 * 8 - 9
  = 123 * 45 - 6 * 7 - 8 - 9 = - 123 * 4 + 5 + 67 * 89
  = 9 * 8 * 76 + 5 + 4 - 3 - 2 */ 1 = 9 * 8 * 76 + 5 + 4 - 3 * 2 + 1
  = 9 * 8 * 76 - 5 + 4 + 3 + 2 */ 1 = 9 * 8 * 76 - 5 + 4 + 3 * 2 - 1
  = 9 * 8 * 76 - 5 + 4 * 3 - 2 - 1 = 9 + 8 + 7 * 65 * 4 * 3 - 2 + 1
  = 9 - 8 + 7 * 6 + 5432 + 1 = 9 * 8 * 76 - 5 - 4 * 3 + 21
  = 9 * 8 * 76 - 5 * 4 + 3 + 21 = 9 * 8 * 76 + 5 + 4 + 3 + 2 - 10
  = 9 * 8 * 76 + 5 * 4 - 3 * 2 - 10 = 9 * 8 * 76 - 5 + 4 - 3 - 2 + 10
  = 9 * 8 * 76 + 5 / 4 * 32 / 10,
742 = 92 * 82 - 72 + 62 + 52 * 42 + 32 - 22 - 102 = 982 + 72 - 652 + 42 * 32 + 22 - 102
  = 982 + 72 - 652 - 42 - 32 * 22 + 102.

(12 + 22 + 32 + ... + 742) = 137825, the first 6-digit integer which consists of different digits.

(742 + 2) = (82 + 2)(92 + 2) = (22 + 2)(32 + 2)(92 + 2),
(742 - 2) = (32 - 2)(282 - 2) = (22 - 2)(52 - 2)(112 - 2) = (32 - 2)(52 - 2)(62 - 2),
(742 + 5) = (42 + 5)(162 + 5).

742 + 752 + 762 + ... + 365542 = 40350662.

12 + 22 + 32 + 42 + ... + 742 = 137825, which consists of different digits.

(1 + 2)(3 + 4 + ... + 24)(25 + 26 + ... + 74) = 14852,
(1 + 2 + 3 + 4 + 5)(6 + 7 + ... + 69)(70 + 71 + ... + 74) = 36002,
(1 + 2 + ... + 10)(11 + 12 + ... + 24)(25 + 26 + ... + 74) = 57752.

(12 + 22 + ... + 242)(252 + 262... + 732)(742) = 18492602.

742 = 5476 appears in the decimal expressions of π and e:
  π = 3.14159•••5476••• (from the 19726th digit),
  e = 2.71828•••5476••• (from the 7557th digit).


Page of Squares : First Upload February 16, 2004 ; Last Revised January 31, 2011
by Yoshio Mimura, Kobe, Japan