A379010 Square array A(n, k) = phi(A246278(n, k)), read by falling antidiagonals; Euler totient function applied to the prime shift array.
1, 2, 2, 2, 6, 4, 4, 8, 20, 6, 4, 18, 24, 42, 10, 4, 12, 100, 60, 110, 12, 6, 24, 40, 294, 120, 156, 16, 8, 20, 120, 72, 1210, 192, 272, 18, 6, 54, 48, 420, 160, 2028, 288, 342, 22, 8, 40, 500, 96, 1320, 216, 4624, 396, 506, 28, 10, 36, 168, 2058, 180, 2496, 352, 6498, 616, 812, 30, 8, 24, 200, 660, 13310, 264, 4896, 504, 11638, 840, 930, 36
Offset: 1
Examples
The top left corner of the array: k= | 1 2 3 4 5 6 7 8 9 10 2k= | 2 4 6 8 10 12 14 16 18 20 ----+------------------------------------------------------------------- 1 | 1, 2, 2, 4, 4, 4, 6, 8, 6, 8, 2 | 2, 6, 8, 18, 12, 24, 20, 54, 40, 36, 3 | 4, 20, 24, 100, 40, 120, 48, 500, 168, 200, 4 | 6, 42, 60, 294, 72, 420, 96, 2058, 660, 504, 5 | 10, 110, 120, 1210, 160, 1320, 180, 13310, 1560, 1760, 6 | 12, 156, 192, 2028, 216, 2496, 264, 26364, 3264, 2808, 7 | 16, 272, 288, 4624, 352, 4896, 448, 78608, 5472, 5984, 8 | 18, 342, 396, 6498, 504, 7524, 540, 123462, 9108, 9576, 9 | 22, 506, 616, 11638, 660, 14168, 792, 267674, 17864, 15180, 10 | 28, 812, 840, 23548, 1008, 24360, 1120, 682892, 26040, 29232, 11 | 30, 930, 1080, 28830, 1200, 33480, 1260, 893730, 39960, 37200, 12 | 36, 1332, 1440, 49284, 1512, 53280, 1656, 1823508, 59040, 55944,
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Crossrefs
Programs
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PARI
up_to = 11325; \\ = binomial(150+1,2) A246278sq(row,col) = if(1==row,2*col, my(f = factor(2*col)); for(i=1, #f~, f[i,1] = prime(primepi(f[i,1])+(row-1))); factorback(f)); A379010sq(row,col) = eulerphi(A246278sq(row,col)); A379010list(up_to) = { my(v = vector(up_to), i=0); for(a=1,oo, for(col=1,a, i++; if(i > up_to, return(v)); v[i] = A379010sq(col,(a-(col-1))))); (v); }; v379010 = A379010list(up_to); A379010(n) = v379010[n];
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