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 A180156 Sequence from adding the twin primes and dividing by the digit sum of twin primes. 0
 1, 1, 4, 2, 4, 7, 6, 8, 34, 12, 12, 14, 13, 16, 11, 19, 23, 20, 24, 52, 23, 40, 48, 39, 58, 35, 40, 41, 54, 40, 60, 69, 46, 41, 49, 136, 172, 100, 118, 91, 128, 117, 71, 78, 217, 126, 95, 121, 99, 71, 107, 120, 79, 71, 144, 75, 104, 78, 129, 100, 74, 169, 174, 116, 352, 203, 238 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS If necessary the result is rounded to the nearest integer. LINKS Table of n, a(n) for n=1..67. Eric Weisstein's World of Mathematics, Twin Primes EXAMPLE (59 + 61) / (5+9+6+1) = 120/21 = 5.7 = 6 (rounded to the nearest integer) 107 and 109 are twin primes. Hence (107 + 109) / (1+0+7+1+0+9) = 216/18 = 12 MATHEMATICA Floor[1/2+Total[#]/Total[Flatten[IntegerDigits/@#]]]&/@ Select[Partition[Prime[Range[500]], 2, 1], Last[#]-First[#]==2&] (* Harvey P. Dale, Mar 23 2011 *) f[n_] := Round[2 (n + 1)/(Plus @@ IntegerDigits[n] + Plus @@ IntegerDigits[n + 2])]; f@# & /@ Select[ Prime@ Range@ 1000, PrimeQ[# + 2] &] (* Robert G. Wilson v, Aug 16 2011 *) CROSSREFS Cf. A001359. Sequence in context: A013679 A096428 A091007 * A110638 A154995 A154973 Adjacent sequences: A180153 A180154 A180155 * A180157 A180158 A180159 KEYWORD base,nonn,less AUTHOR Parthasarathy Nambi, Aug 14 2010 EXTENSIONS More terms from Harvey P. Dale, Mar 23 2011. STATUS approved

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Last modified September 9 16:40 EDT 2024. Contains 375765 sequences. (Running on oeis4.)