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A077321 Rearrange primes so as to form a triangle in which n-th row contains the n smallest primes == 1 (mod n) which have not occurred earlier.

%I A077321 #19 May 30 2023 07:43:15
%S A077321 2,3,5,7,13,19,17,29,37,41,11,31,61,71,101,43,67,73,79,97,103,113,127,
%T A077321 197,211,239,281,337,89,137,193,233,241,257,313,353,109,163,181,199,
%U A077321 271,307,379,397,433,131,151,191,251,311,331,401,421,431,461,23,419,463,617
%N A077321 Rearrange primes so as to form a triangle in which n-th row contains the n smallest primes == 1 (mod n) which have not occurred earlier.
%H A077321 Ivan Neretin, <a href="/A077321/b077321.txt">Table of n, a(n) for n = 1..5050</a>
%e A077321 Triangle begins:
%e A077321 2
%e A077321 3 5
%e A077321 7 13 19
%e A077321 17 29 37 41
%e A077321 11 31 61 71 101
%e A077321 ...
%p A077321 A077321 := proc(nmax) local n,a,i,p; a := []; n :=1; while nops(a) < nmax do for i from 1 to n do p := 2; while ( p in a ) or (p-1) mod n <> 0 do p := nextprime(p); od; a := [op(a),p]; od; n := n+1; od; RETURN(a); end: A077321(100); # _R. J. Mathar_, Feb 03 2007
%t A077321 A077321[nmax_] := Module[{n = 1, a = {}, i, p}, While[ Length[a] < nmax, For[i = 1, i <= n, i++,  p = 2; While[ MemberQ[a, p] || Mod[p - 1, n] != 0, p = NextPrime[p]]; a = Append[a, p]]; n = n + 1]; Return[a]];
%t A077321 A077321[100] (* _Jean-François Alcover_, May 30 2023, after _R. J. Mathar_ *)
%Y A077321 Cf. A077322, A077323, A077324, A077325.
%Y A077321 Cf. A100787, A100788, A100789, A100790.
%K A077321 nonn,tabl
%O A077321 1,1
%A A077321 _Amarnath Murthy_, Nov 04 2002, Nov 30 2004
%E A077321 More terms from _Ray Chandler_, Dec 10 2004
%E A077321 Edited by _N. J. A. Sloane_, Sep 14 2008 at the suggestion of _R. J. Mathar_