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A074912 Triangle generated by Pascal's rule, except begin and end the n-th row with phi(n). 1
1, 1, 1, 2, 2, 2, 2, 4, 4, 2, 4, 6, 8, 6, 4, 2, 10, 14, 14, 10, 2, 6, 12, 24, 28, 24, 12, 6, 4, 18, 36, 52, 52, 36, 18, 4, 6, 22, 54, 88, 104, 88, 54, 22, 6, 4, 28, 76, 142, 192, 192, 142, 76, 28, 4, 10, 32, 104, 218, 334, 384, 334, 218, 104, 32, 10 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..66.

EXAMPLE

1;

1,1;

2,2,2;

2,4,4,2;

4,6,8,6,4;

2,10,14,14,10,2;

6,12,24,28,24,12,6;

4,18,36,52,52,36,18,4;

6,22,54,88,104,88,54,22,6;

4,28,76,142,192,192,142,76,28,4;

MAPLE

A074912 := proc(n, k) if k=1 or k=n then numtheory[phi](n); elif k > n or k < 1 then 0; else procname(n-1, k-1)+procname(n-1, k) ; end if; end proc: seq(seq(A074912(n, k), k=1..n), n=1..12); # R. J. Mathar, Aug 24 2011

PROG

(PARI) t(n, k) = {if ((k<1) || (k>n), return (0)); if ((k==1) || (k==n), return (eulerphi(n))); return (t(n-1, k-1)+t(n-1, k)); }

tabl(nn) = {for (n=1, nn, for (k=1, n, print1(t(n, k), ", "); ); /* print(); */); } \\ Michel Marcus, Nov 13 2014

CROSSREFS

Sequence in context: A277847 A085311 A052273 * A274207 A158502 A215244

Adjacent sequences:  A074909 A074910 A074911 * A074913 A074914 A074915

KEYWORD

easy,nonn,tabl

AUTHOR

Joseph L. Pe, Oct 01 2002

EXTENSIONS

More terms from Michel Marcus, Nov 13 2014

STATUS

approved

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Last modified April 23 22:41 EDT 2019. Contains 322389 sequences. (Running on oeis4.)