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# ãã㯠(a[2n])^2=a[2n-1]a[2n+1]-2 ãš a[n+2]=2a[n+1]+a[n] ãã瀺ããŸãã
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(4^2-1)(31^2-1)=(11^2-1)^2
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(4^2-1)(31^2-1)=(11^2-1)^2
(2^2-1)(97^2-1)=(13^2-1)^2
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9^2+10^2=181
11^2+12^2+13^2=434
6^2+7^2+8^2+9^2+10^2+11^2+12^2=595
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ãã®åæçæ°ã®å€§ããã10000000以äžã§ãããã®ãšããæ¡ä»¶ã®ãšã
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10000000以äžã§ã¯554455ãš9343439ã®2åã§ãããã
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ã100000000000000以äžãã«ããŠã1åããå¢ããŸããã§ããã
9^2+10^2+âŠ+118^2 = 554455
331^2+332^2+âŠ+335^2 = 554455
102^2+103^2+âŠ+307^2 = 9343439
657^2+658^2+âŠ+677^2 = 9343439
2967^2+2968^2+âŠ+14087^2 = 923222222329
42462^2+42463^2+âŠ+42967^2 = 923222222329
(è¿œèš)
çããâããã«ãããŸããã
https://oeis.org/A267600
æšå¹ŽããProject Eulerã®åé¡ãproblem1 ããé çªã«ããã°ã©ã ã®ç·Žç¿ã«ãšè§£ããŠããŠ
https://projecteuler.net/about
problem=125ã«Palindromic Sumsã®ããŒãã®åé¡ã«ïŒhttps://projecteuler.net/problem=125ïŒ
åœãã£ãŠããã
ããããèŠåŽããªãã3æ¥äœãããã£ãš
the sum of all the numbers less than 10^8
that are both palindromic and can be written as the sum of consecutive squares.
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a(4) > 10^18, if it exists
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