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 A162424 Square table defined by T(n,k) = Sum_{m=k(k+1)/2..k(k+1)/2+k} [x^m] S(x)^n for n>=1, k>=0, where S(x) = Sum_{n>=0} x^((n+1)(n+2)/2-1), as read by antidiagonals. 6
 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 5, 10, 13, 7, 1, 1, 6, 15, 33, 24, 7, 1, 1, 7, 21, 70, 68, 34, 8, 1, 1, 8, 28, 131, 171, 123, 49, 11, 1, 1, 9, 36, 224, 388, 385, 226, 69, 13, 1, 1, 10, 45, 358, 806, 1073, 836, 342, 94, 13, 1, 1, 11, 55, 543, 1556, 2709, 2674, 1485, 547 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Table of n, a(n) for n=1..74. EXAMPLE This table begins: 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,... 1,2,3,4,7,7,8,11,13,13,16,15,19,22,21,23,22,29,27,31,30,29,39,34,... 1,3,6,13,24,34,49,69,94,117,148,174,211,249,298,331,366,439,498,... 1,4,10,33,68,123,226,342,547,778,1071,1412,1901,2392,2997,3762,... 1,5,15,70,171,385,836,1485,2630,4271,6590,9536,14030,19286,25995,... 1,6,21,131,388,1073,2674,5634,11173,20379,35305,56757,89734,... 1,7,28,224,806,2709,7749,19055,42770,87773,168778,302008,519407,... 1,8,36,358,1556,6303,20792,58846,150169,346748,737442,1464203,... 1,9,45,543,2829,13711,52221,168912,489993,1269145,2990595,... 1,10,55,790,4897,28191,123717,455882,1499600,4345078,11360122,... 1,11,66,1111,8140,55231,278334,1166066,4335837,14032832,... 1,12,78,1519,13080,103742,598217,2843920,11916721,43041924,... ... Let coefficients in powers of the series: S = 1 + x^2 + x^5 + x^9 + x^14 + x^20 + x^27 + x^35 + x^44 +... form the following sequences: S^1: [(1),(0,1),(0,0,1),(0,0,0,1),(0,0,0,0,1),(0,0,0,0,0,1),...] S^2: [(1),(0,2),(0,1,2),(0,2,0,2),(1,2,0,0,4),(0,2,0,1,2,2),...] S^3: [(1),(0,3),(0,3,3),(1,6,0,6),(3,6,3,3,9),(1,12,0,6,9,6),...] S^4: [(1),(0,4),(0,6,4),(4,12,1,16),(6,16,12,12,12),...] S^5: [(1),(0,5),(0,10,5),(10,20,5,35),(11,40,30,35,35),...] S^6: [(1),(0,6),(0,15,6),(20,30,15,66),(21,90,61,90,126),...] S^7: [(1),(0,7),(0,21,7),(35,42,35,112),(42,182,112,210),...] S^8: [(1),(0,8),(0,28,8),(56,56,70,176),(84,336,196,448),...] S^9: [(1),(0,9),(0,36,9),(84,72,126,261),(162,576,336,882),...] S^10:[(1),(0,10),(0,45,10),(120,90,210,370),(297,930,570,1620),...] ... then the sums of the above grouped terms (enclosed in parenthesis) form the initial terms of the rows of this table: T(3,4) = (3+6+3+3+9) = 24 ; T(4,3) = (4+12+1+16) = 33 ; T(5,3) = (10+20+5+35) = 70. Summing the coefficients of S^n in this way generates all the rows of this table. PROG (PARI) {T(n, k)=local(S=sum(m=0, k+1, x^((m+1)*(m+2)/2-1))+O(x^((k+2)*(k+3)/2))); sum(m=k*(k+1)/2, k*(k+1)/2+k, polcoeff(S^n, m))} CROSSREFS Cf. rows: A162425, A162426, A162427. Cf. A162428 (antidiagonal sums), A162429 (main diagonal). Cf. A162430 (variant). Sequence in context: A197061 A230861 A119724 * A302998 A303484 A008571 Adjacent sequences: A162421 A162422 A162423 * A162425 A162426 A162427 KEYWORD nonn,tabl AUTHOR Paul D. Hanna, Jul 03 2009 STATUS approved

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Last modified July 22 22:21 EDT 2024. Contains 374544 sequences. (Running on oeis4.)