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 A303340 Binary expansion of constant: B = Sum_{n>=1} (-1)^(n-1) / (2^n - 1)^n. 2
 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0 LINKS FORMULA This constant may be defined by the following expressions. (1) B = Sum_{n>=1} (-1)^(n-1) / (2^n - 1)^n. (2) B = Sum_{n>=1} (2^n - 1)^(n-1) / 2^(n^2). (3) B = Sum_{n>=1} A303506(n)/2^n where A303506(n) = Sum_{d|n} binomial(n/d-1, d-1) * (-1)^(d-1) for n>=1. EXAMPLE In base  2: B = 0.11100100010010111111111100111101001100001001001100... In base 10: B = 0.891784622610953349715890136060239421022216970366139... This constant equals the sum of the following infinite series. (1) B = 1 - 1/3^2 + 1/7^3 - 1/15^4 + 1/31^5 - 1/63^6 + 1/127^7 - 1/255^8 + 1/511^9 - 1/1023^10 + 1/2047^11 - 1/4095^12 + 1/8191^13 - 1/16383^14 + ... Also, (2) B = 1/2 + 3/2^4 + 7^2/2^9 + 15^3/2^16 + 31^4/2^25 + 63^5/2^36 + 127^6/2^49 + 255^7/2^64 + 511^8/2^81 + 1023^9/2^100 + 2047^10/2^121 + 4095^11/2^144 + ... Expressed in terms of powers of 1/2, we have (3) B = 1/2 + 1/2^2 + 1/2^3 + 0/2^4 + 1/2^5 - 1/2^6 + 1/2^7 - 2/2^8 + 2/2^9 - 3/2^10 + 1/2^11 - 1/2^12 + 1/2^13 - 5/2^14 + 7/2^15 - 7/2^16 + 1/2^17 + 3/2^18 + 1/2^19 - 12/2^20 + 16/2^21 - 9/2^22 + ... + A303506(n)/2^n + ... The binary expansion of this constant begins: B = 0.11100100010010111111111100111101001100001001001100\ 11111010000100110110010100000011000111010001001111\ 01010101000100000011111100001011011110100001111110\ 00011100101101000101010111011000011001000010101000\ 01001101100101010110001001110110001101010000111011\ 11110111011111000101010011100001111110011111011011\ 00001001000101000101100000000010101111100010001111\ 10100001111001110011001100011110110001010001100100\ 10101000101110001000111001010110110111101010011011\ 00100111110000000001101111110010000010110001111101\ 00101101000000110001000010100011111001100010100001\ 10100000001011000111111010111100100110100101011101\ 01010000001001000100000011101111110011001010001011\ 00000111011010111010100000110110111111111100111001\ 11011011110001111100010010011111000010000100001011\ 00011101110101100100011001101110011001111111001001\ 10011101110010111110111111010110101110001110001000\ 00111110001010100101111000110010101011000101000111\ 10111001011111000000101000111001001010100100010000\ 00111111111001110011101011111110010000000010111100\ 11111110000100100011101010110100100010001100010111\ 10000110111011001111011000100001101110100100001000\ 00010000010111011111011000000011100110100100111111\ 00110000010111110010110011001111010110011001000101\ 11110001000111111001111001100001001100000101010000\ 01100100111000100011010000101000100101100100111010\ 00100111111011110010101110000101010110110101000010\ 10111001001110101101100010101110010110011010100100\ 00001110111111000000101111000111000110110111111111\ 10000010011101001001010101000001001010000010101111\ 11000100010111110001011011101100011001011000101101\ 00010010001010000011110101111000110100001101010111\ 00000111111001000011000100111101110101001111110110\ 01000111010110100010100010101000110000100101001001\ 11111101110111001100011111111100100000011110001100\ 01111011011100011001010100110010110010011100111001\ 11011100010110001100010001101110111101100110111111\ 10011110000010100100100010010011011110110010111100\ 00110101110110110110100001110011110111110001101110\ 11010011010111010110001000000100101110011010110010... MATHEMATICA bits = 200; B = NSum[(-1)^(n-1)/(2^n-1)^n, {n, 1, Infinity}, Method -> "AlternatingSigns", WorkingPrecision -> Ceiling[Log[10, 2]*bits]]; RealDigits[B, 2, bits][[1]] (* Jean-François Alcover, Apr 25 2018 *) CROSSREFS Cf. A302765 (decimal expansion), A303506. Sequence in context: A096606 A128190 A128189 * A115512 A115513 A133080 Adjacent sequences:  A303337 A303338 A303339 * A303341 A303342 A303343 KEYWORD nonn,cons AUTHOR Paul D. Hanna, Apr 24 2018 STATUS approved

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Last modified June 13 00:57 EDT 2021. Contains 344980 sequences. (Running on oeis4.)