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 A257253 Square array A(row,col) = (1/2) * (A083221(row,col+1) - A083221(row,col)): half of the first differences of each row of array constructed from the sieve of Eratosthenes. 4
 1, 1, 3, 1, 3, 10, 1, 3, 5, 21, 1, 3, 10, 14, 55, 1, 3, 5, 7, 11, 78, 1, 3, 10, 14, 22, 26, 136, 1, 3, 5, 7, 11, 13, 17, 171, 1, 3, 10, 14, 22, 26, 34, 38, 253, 1, 3, 5, 21, 33, 39, 51, 57, 69, 406, 1, 3, 10, 7, 11, 13, 17, 19, 23, 29, 465 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The array A(row,col) is read by its downwards antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), ... LINKS Antti Karttunen, Table of n, a(n) for n = 1..3321; the first 81 antidiagonals of the array FORMULA A(row,col) = (1/2) * (A083221(row,col+1) - A083221(row,col)). A(row,col) = A257251(row,col)/2. EXAMPLE The top left corner of the array: 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 10, 5, 10, 5, 10, 5, 10, 5, 10, 5, 10, 5, 10, 5, 10 21, 14, 7, 14, 7, 14, 21, 7, 21, 14, 7, 14, 7, 14, 21 55, 11, 22, 11, 22, 33, 11, 33, 22, 11, 22, 33, 33, 11, 33 78, 26, 13, 26, 39, 13, 39, 26, 13, 26, 39, 39, 13, 39, 26 136, 17, 34, 51, 17, 51, 34, 17, 34, 51, 51, 17, 51, 34, 17 171, 38, 57, 19, 57, 38, 19, 38, 57, 57, 19, 57, 38, 19, 57 253, 69, 23, 69, 46, 23, 46, 69, 69, 23, 69, 46, 23, 69, 46 406, 29, 87, 58, 29, 58, 87, 87, 29, 87, 58, 29, 87, 58, 87 465, 93, 62, 31, 62, 93, 93, 31, 93, 62, 31, 93, 62, 93, 124 666, 74, 37, 74, 111, 111, 37, 111, 74, 37, 111, 74, 111, 148, 74 820, 41, 82, 123, 123, 41, 123, 82, 41, 123, 82, 123, 164, 82, 41 903, 86, 129, 129, 43, 129, 86, 43, 129, 86, 129, 172, 86, 43, 86 1081, 141, 141, 47, 141, 94, 47, 141, 94, 141, 188, 94, 47, 94, 47 1378, 159, 53, 159, 106, 53, 159, 106, 159, 212, 106, 53, 106, 53, 106 ... PROG (Scheme) (define (A257253 n) (A257253bi (A002260 n) (A004736 n))) (define (A257253bi row col) (* (/ 1 2) (- (A083221bi row (+ 1 col)) (A083221bi row col)))) ;; Code for A083221bi given in A083221. CROSSREFS Transpose: A257254. Cf. A083221, A257251 (same array but with terms multiplied by 2). Column 1: A008837. Row 4: (7/2) * A145011. Sequence in context: A058842 A155734 A128162 * A067329 A170860 A170845 Adjacent sequences: A257250 A257251 A257252 * A257254 A257255 A257256 KEYWORD nonn,tabl AUTHOR Antti Karttunen, Apr 29 2015 STATUS approved

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Last modified September 27 20:41 EDT 2023. Contains 365714 sequences. (Running on oeis4.)