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A269415 a(n) is the smallest positive integer not already in the sequence such that Sum_{i=1..n} digital_sum(a(i)) is prime. 3
2, 1, 4, 6, 13, 11, 19, 8, 15, 22, 24, 17, 28, 20, 33, 31, 42, 26, 37, 51, 59, 39, 46, 35, 55, 48, 57, 44, 66, 75, 40, 60, 53, 64, 84, 62, 73, 93, 68, 82, 77, 79, 101, 91, 71, 88, 86, 103, 80, 109, 95, 97, 99, 129, 107, 112, 116, 118, 138, 110, 189, 105, 127, 114, 123, 125, 136, 132, 134, 141, 145, 149, 147, 121, 150, 143, 156, 130, 158, 154, 152, 163 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The sequence starts with a(1) = 2 and is always extended with the smallest integer not yet present that does not lead to a contradiction.
LINKS
Jean-Marc Falcoz and Chai Wah Wu, Table of n, a(n) for n = 1..10000 Terms for n = 1..2018 from Jean-Marc Falcoz
EXAMPLE
The sequence starts with 2, 1, 4, 6, 13, 11, 19, 8, 15, 22... which produces the partial sums (of digits) 2, 3 (=2+1), 7 (=3+4), 13 (=7+6), 17 (=13+1+3), 19 (=17+1+1), 29 (=19+1+9)... Those successive partial sums of digits are all prime.
MATHEMATICA
A269415L[n_] := Module[{lis = {}, b = 0}, Do[Do[If[! MemberQ[lis, a] && PrimeQ[b + Total[IntegerDigits[a]]], lis = Append[lis, a]; b += Total[IntegerDigits[a]]; Break[]], {a, Infinity}], {max, n}]; lis]; A269415L[82] (* JungHwan Min, Nov 09 2016 *)
CROSSREFS
For records see A278031. For a binary version see A278032.
Sequence in context: A095012 A192781 A253918 * A367716 A019142 A330536
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified March 29 10:44 EDT 2024. Contains 371268 sequences. (Running on oeis4.)