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 A266603 Irregular triangle T(n,k) read by rows: numbers such that 2^n +/- T(n,k) are both primes. 0
 0, 1, 3, 5, 3, 13, 9, 15, 21, 29, 3, 33, 45, 21, 39, 45, 69, 99, 105, 111, 15, 27, 57, 75, 93, 117, 153, 177, 183, 243, 253, 9, 45, 81, 129, 165, 231, 249, 261, 285, 315, 345, 375, 399, 441, 459, 465, 471, 501 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Except when k is maximum for a given n, all elements must be odd multiples of 3. Specifically: T(n,k) == {9,15,21} mod 30 when n is odd and T(n,k) == {3,15,27} mod 30 when n is even. The only exception is T(3,1)=3. LINKS EXAMPLE Triangle starting with T(1,1): 0 1 3 5 3 13 9 15 21 29 3 33 45 21 39 45 69 99 105 111 15 27 57 75 93 117 153 177 183 243 253 9 45 81 129 165 231 249 261 285 315 345 375 399 441 459 465 471 501 ... T(5,4)=29 because 2^5=32; 32+29=61 and 32-29=3 are prime. CROSSREFS Cf. A000040 (prime numbers). Sequence in context: A089948 A336806 A023583 * A121278 A023587 A172003 Adjacent sequences: A266600 A266601 A266602 * A266604 A266605 A266606 KEYWORD nonn,tabf AUTHOR Bob Selcoe, Feb 21 2016 STATUS approved

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Last modified March 24 22:08 EDT 2023. Contains 361511 sequences. (Running on oeis4.)