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A178623 Triangle T(n,m) read by rows: T(n,0)= prime(n); T(n,m)=1 if m>=1. 0
1, 2, 1, 3, 1, 1, 5, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 17, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 19, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 23, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 29 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The sequence reflects a conjecture on the denominator of inverse Bernoulli polynomials in A178340: if the row index is one less than one of the primes in A008578, the row of denominators starts with that prime and contains 1's in the remaining entries.

[Row sums in A178252 are A159069(n+1), unless there is a common factor in numerator and denominator. The row sum over columns with index of the same parity as the row index in the table of fractions of the [x^m] B^{-1}(n,x) in A178252 are: 1, 1, 1/3+1=4/3, 1+1=2, 1/5+2+1=16/5, 1+10/3+1=16/3, 1/7+3+5+1=64/7, 16, 256/9, 256/5, 1024/11, 512/3, 496/13, ... =A084623(n+1)/A000265(n+1).]

LINKS

Table of n, a(n) for n=0..101.

FORMULA

T(n,0) = A008578(n+1). T(n,m) =1, 1<=m<=A008578(n+1)-1.

EXAMPLE

1;

2,1;

3,1,1;

5,1,1,1,1;

7,1,1,1,1,1,1;

11,1,1,1,1,1,1,1,1,1,1;

13,1,1,1,1,1,1,1,1,1,1,1,1;

17,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1;

19,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1;

23,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1;

29,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1;

CROSSREFS

Cf. A076274 (row sums).

Sequence in context: A294099 A209115 A141412 * A210765 A160183 A168534

Adjacent sequences:  A178620 A178621 A178622 * A178624 A178625 A178626

KEYWORD

nonn,tabf,easy,less

AUTHOR

Paul Curtz, May 31 2010

STATUS

approved

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Last modified November 27 16:20 EST 2021. Contains 349394 sequences. (Running on oeis4.)