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A144562 Triangle read by rows: T(n, k) = 2nk + n + k - 1. 34
3, 6, 11, 9, 16, 23, 12, 21, 30, 39, 15, 26, 37, 48, 59, 18, 31, 44, 57, 70, 83, 21, 36, 51, 66, 81, 96, 111, 24, 41, 58, 75, 92, 109, 126, 143, 27, 46, 65, 84, 103, 122, 141, 160, 179, 30, 51, 72, 93, 114, 135, 156, 177, 198, 219, 33, 56, 79, 102, 125, 148, 171, 194 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Rearrangement of A153238, numbers n such that 2*n+3 is not prime (we have 2*T(n,k)+3=(2*n+1)*(2*k+1), as 2*n+3 is odd it consists of (at least) two odd factors and all such factors appear by definition).

LINKS

Vincenzo Librandi, Rows n = 1..100, flattened

Mutsumi Suzuki Vincenzo Librandi's method for sequential primes (Librandi's description in Italian).

EXAMPLE

Triangle begins:

3;

6, 11;

9, 16, 23;

12, 21, 30, 39;

15, 26, 37, 48, 59;

18, 31, 44, 57, 70, 83;

21, 36, 51, 66, 81, 96, 111;

24, 41, 58, 75, 92, 109, 126, 143;

27, 46, 65, 84, 103, 122, 141, 160, 179;

MATHEMATICA

t[n_, k_] := 2 n*k + n + k - 1; Table[t[n, k], {n, 11}, {k, n}] // Flatten

PROG

(MAGMA) [2*n*k+n+k-1: k in [1..n], n in [1..11]]; /* or, see example: */ [[2*n*k+n+k-1: k in [1..n]]: n in [1..9]]; // Bruno Berselli, Dec 04 2011

(PARI) T(n, k)=2*n*k+n+k-1 \\ Charles R Greathouse IV, Dec 28 2011

CROSSREFS

Cf. A067076, A153238.

Sequence in context: A006509 A325551 A258928 * A102889 A183543 A256108

Adjacent sequences:  A144559 A144560 A144561 * A144563 A144564 A144565

KEYWORD

nonn,easy,tabl

AUTHOR

Vincenzo Librandi, Jan 06 2009

EXTENSIONS

Edited by Ray Chandler, Jan 07 2009

STATUS

approved

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Last modified June 3 05:29 EDT 2020. Contains 334798 sequences. (Running on oeis4.)