A087478 -id:A087478 - cp's OEIS frontend

A087477 Decimal expansion of sqrt(51)-4.

3, 1, 4, 1, 4, 2, 8, 4, 2, 8, 5, 4, 2, 8, 4, 9, 9, 9, 7, 9, 9, 9, 3, 9, 9, 8, 1, 1, 3, 6, 7, 2, 6, 5, 2, 7, 8, 7, 6, 6, 1, 7, 1, 1, 5, 9, 9, 0, 2, 7, 3, 3, 8, 3, 3, 2, 0, 8, 4, 3, 0, 8, 8, 2, 7, 6, 5, 8, 2, 0, 4, 0, 6, 4, 4, 0, 0, 2, 1, 8, 8, 6, 2, 5, 8, 9, 8, 8, 2, 1, 3, 5, 3, 2, 8, 2, 0, 4, 1, 8

Offset: 1

Zak Seidov, Sep 09 2003

A simple approximation to Pi, see also A087478.

			3.14142842854284999799939981136726527876617115990273...

Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Cf. A000796, A010504, A087478.

RealDigits[Sqrt[51] - 4, 10, 120][[1]] (* Amiram Eldar, May 16 2023 *)

Equals A010504 minus 4. - R. J. Mathar, Sep 11 2008

A363672 Triangular array: row n lists the primes indexed by the array in A363671.

Original entry on oeis.org

2, 2, 3, 3, 5, 7, 2, 5, 7, 11, 3, 5, 11, 13, 17, 2, 5, 7, 13, 17, 19, 3, 5, 11, 13, 19, 23, 29, 5, 11, 13, 19, 23, 31, 37, 41, 2, 7, 13, 17, 23, 29, 37, 41, 43, 5, 7, 17, 23, 29, 37, 41, 47, 53, 59, 3, 11, 13, 23, 31, 37, 43, 47, 59, 61, 67, 2, 5, 13, 17, 29

Offset: 1

Clark Kimberling, Jun 15 2023

Row n lists primes of the form prime(n+2)-2*k where A028334(n) <= k <= A067076(n).

			First 10 rows:
  2
  2    4
  3    5    7
  2    5    7   11
  3    5   11   13   17
  2    5    7   13   17   19
  3    5   11   13   19   23   29
  5   11   13   19   23   31   37   41
  2    7   13   17   23   29   37   41   43
  5    7   17   23   29   37   41   47   53   59
For row 6, we have prime(8) = 19, and prime 19-2*k is prime for these k: 1, 3, 4, 6, 7, 8. The primes with indexes 1,3,4,6,7,8 are 2,5,7,13,17,19.

Cf. A000040, A087478 (column 1), A363671.

m[p_] := Select[Range[500], PrimeQ[p - 2 #] && p > 2 # &]
t = Prime[Table[m[Prime[n]], {n, 3, 15}]]
TableForm[t]  (* this sequence as an array *)
Flatten[t]    (* this sequence *)

cp's OEIS Frontend

A087477 Decimal expansion of sqrt(51)-4.

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