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 A123257 Multiplicative encoding of nim sum triangle: Product p(i+1)^BitXOR(n,i). 0
 2, 6, 100, 9261000, 103306896, 16274381169926880, 98925457477919384169000000, 8078021071852487276180833326494285813758890000000, 20381485968895666256747501044033896769440000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS This is to A003987 "Table of n XOR m (or Nim-sum of n and m)" as A007188 "Multiplicative encoding of Pascal triangle: Product p(i+1)^C(n,i)" is to A007318 "Pascal's triangle read by rows." T[2i,2j] = 2T[i,j], T[2i+1,2j] = 2T[i,j] + 1. a(2^n-1) = (n#)^(2^n-1) = A002110(n)^A000225(n). LINKS Table of n, a(n) for n=1..9. FORMULA a(n) = Prod[i=i..n] p(i+1)^BitXOR(n,i). EXAMPLE a(1) = p(1)^T(1,1) = 2^1 = 2, where T(i,j) is as in A003987. a(2) = p(1)^T(2,1) * p(2)^T(2,2) = 2^1 * 3^1 = 6. a(3) = p(1)^T(3,1) * p(2)^T(3,2) * p(3)^T(3,3) = 2^2 * 3^0 * 5^2 = 100. a(4) = 2^3 * 3^3 * 5^3 * 7^3 = 9261000. a(5) = 2^4 * 3^2 * 5^0 * 7^2 * 11^4 = 103306896. a(6) = 2^5 * 3^5 * 5^1 * 7^1 * 11^5 * 13^5 = 16274381169926880. a(7) = 2^6 * 3^4 * 5^6 * 7^0 * 11^6 * 13^4 * 17^6 = 98925457477919384169000000. a(8) = 2^7 * 3^7 * 5^7 * 7^7 * 11^7 * 13^7 * 17^7 * 19^7. a(9) = 2^8 * 3^6 * 5^4 * 7^6 * 11^0 * 13^6 * 17^4 * 19^6 * 23^8. a(10) = 2^9 * 3^9 * 5^5 * 7^5 * 11^1 * 13^1 * 17^5 * 19^5 * 23^9 * 29^9. CROSSREFS Cf. A000040, A000225, A002110, A003987, A007188, A007318, A009766, A124061. Sequence in context: A066091 A100704 A357084 * A230927 A054247 A278888 Adjacent sequences: A123254 A123255 A123256 * A123258 A123259 A123260 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, Nov 06 2006 STATUS approved

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Last modified August 6 03:16 EDT 2024. Contains 374957 sequences. (Running on oeis4.)