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 A078497 The member r of a triple of primes (p,q,r) in arithmetic progression which sum to 3*prime(n) = A001748(n) = p + q + r. 5
 7, 11, 17, 19, 23, 31, 29, 41, 43, 43, 53, 67, 53, 59, 71, 79, 73, 83, 79, 97, 107, 107, 127, 113, 109, 113, 139, 137, 151, 149, 167, 151, 167, 163, 163, 199, 197, 179, 191, 199, 233, 223, 227, 241, 223, 283, 257, 277, 239, 251, 271, 263, 263, 269, 281, 313 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,1 COMMENTS In case more than one triple of primes p, q=p+d and r=p+2*d exists, we take r=a(n) from the triple with the smallest d. This shows the difference from A092940, which would take the maximum r over all triples. - R. J. Mathar, May 19 2007 LINKS Table of n, a(n) for n=3..58. EXAMPLE a(1) = 7 because 3+5+7 = 15; a(2) = 11 because 3+7+11 = 21; a(3) = 17 because 5+11+17= 33. MAPLE A078497 := proc(n) local p3, i, d, r, p; p3 := ithprime(n) ; i := n+1 ; while true do r := ithprime(i) ; d := r-p3 ; p := p3-d ; if isprime(p) then RETURN(r) ; fi ; i := i+1 ; od ; RETURN(-1) ; end: for n from 3 to 60 do printf("%d, ", A078497(n)) ; od ; # R. J. Mathar, May 19 2007 MATHEMATICA f[n_] := Block[{p = Prime[n], k}, k = p + 1; While[ !PrimeQ[k] || !PrimeQ[2p - k], k++ ]; k]; Table[ f[n], {n, 3, 60}] CROSSREFS Cf. A078496, A078498, A001748, A092940, A071681, A078611. Sequence in context: A038880 A019365 A191055 * A274505 A256567 A155048 Adjacent sequences: A078494 A078495 A078496 * A078498 A078499 A078500 KEYWORD nonn AUTHOR Serhat Sevki Dincer (sevki(AT)ug.bilkent.edu.tr), Nov 27 2002 EXTENSIONS Edited and extended by Robert G. Wilson v, Nov 29 2002 Further edited by N. J. A. Sloane, Jul 03 2008 at the suggestion of R. J. Mathar STATUS approved

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Last modified December 3 22:01 EST 2023. Contains 367540 sequences. (Running on oeis4.)