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A176653 A symmetrical triangle sequence:: f(n) = If[n == 0, 1, Prime[n]]; t(n, m) = f(n - m)*f(n)-f(n - 0)*f(0) + 1 1
1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 4, 3, 4, 1, 1, 4, 5, 5, 4, 1, 1, 10, 9, 13, 9, 10, 1, 1, 10, 17, 19, 19, 17, 10, 1, 1, 16, 21, 37, 31, 37, 21, 16, 1, 1, 16, 29, 43, 55, 55, 43, 29, 16, 1, 1, 18, 29, 57, 63, 93, 63, 57, 29, 18, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Row sums are:

{1, 2, 4, 6, 13, 20, 53, 94, 181, 288, 429,...}.

LINKS

Table of n, a(n) for n=0..65.

FORMULA

f(n) = If[n == 0, 1, Prime[n]];

t(n, m) = f(n - m)*f(n)-f(n - 0)*f(0) + 1

EXAMPLE

{1},

{1, 1},

{1, 2, 1},

{1, 2, 2, 1},

{1, 4, 3, 4, 1},

{1, 4, 5, 5, 4, 1},

{1, 10, 9, 13, 9, 10, 1},

{1, 10, 17, 19, 19, 17, 10, 1},

{1, 16, 21, 37, 31, 37, 21, 16, 1},

{1, 16, 29, 43, 55, 55, 43, 29, 16, 1},

{1, 18, 29, 57, 63, 93, 63, 57, 29, 18, 1}

MATHEMATICA

Clear[f, t, n, m];

f[n_] := If[n == 0, 1, Prime[n]];

t[n_, m_] = f[n - m]*f[m] - f[n - 0]*f[0] + 1;

Table[t[n, m], {n, 0, 10}, {m, 0, n}]

Flatten[%]

CROSSREFS

Cf. A146985

Sequence in context: A240656 A106476 A101566 * A174842 A156074 A051287

Adjacent sequences:  A176650 A176651 A176652 * A176654 A176655 A176656

KEYWORD

nonn,tabl,uned

AUTHOR

Roger L. Bagula, Apr 22 2010

STATUS

approved

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Last modified January 22 18:28 EST 2019. Contains 319365 sequences. (Running on oeis4.)