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 A075402 Smallest number such that a(n) + T(n) is a prime, where T(n) is the n-th triangular number. 4
 1, 0, 1, 1, 2, 2, 1, 1, 2, 4, 1, 1, 6, 2, 7, 1, 4, 2, 1, 1, 2, 4, 1, 7, 6, 2, 1, 3, 4, 2, 3, 13, 2, 4, 1, 7, 6, 2, 7, 1, 2, 4, 1, 1, 4, 6, 1, 5, 4, 2, 1, 3, 2, 2, 3, 1, 4, 10, 7, 1, 10, 20, 1, 1, 8, 2, 3, 1, 2, 18, 1, 5, 6, 2, 1, 1, 8, 2, 3, 11, 2, 4, 5, 1, 4, 20, 5, 1, 2, 4, 15, 5, 2, 16, 1, 1, 6, 10, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS 0 occurs only once in this sequence. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 MATHEMATICA If[PrimeQ[#], #, NextPrime[#]]-#&/@Accumulate[Range[100]] (* Harvey P. Dale, Nov 21 2012 *) PROG (PARI) for(n=1, 100, a=n*(n+1)/2:print1(nextprime(a)-a", ")) CROSSREFS Cf. A075403. Sequence in context: A240168 A199204 A262750 * A373270 A276696 A220777 Adjacent sequences: A075399 A075400 A075401 * A075403 A075404 A075405 KEYWORD nonn AUTHOR Amarnath Murthy, Sep 23 2002 EXTENSIONS Corrected and extended by Ralf Stephan, Mar 19 2003 STATUS approved

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Last modified September 12 20:35 EDT 2024. Contains 375854 sequences. (Running on oeis4.)