The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A276852 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A276852

Number of positive walks with n steps {-3,-2,-1,1,2,3} starting at the origin, ending at altitude 1, and staying strictly above the x-axis.
(history; published version)

#19 by Davin Park at Mon Oct 10 15:28:49 EDT 2016

MATHEMATICA

A276852[n_] := dp[n, 1, 3]; (* _Davin Park_, Oct 10 2016 *)

#18 by Davin Park at Mon Oct 10 15:25:58 EDT 2016

MATHEMATICA

dp[n_, k_, h_] = 0;

dp[1, k_, h_] := Boole[0 < k <= h];

dp[n_, k_, h_] /; n >= 2 && k > 0 := dp[n, k, h] = Sum[dp[n - 1, k - x, h], {x, h}] + Sum[dp[n - 1, k + x, h], {x, h}];

A276852[n_] := dp[n, 1, 3];

STATUS

approved

editing

#17 by Vaclav Kotesovec at Sat Sep 24 05:56:48 EDT 2016

STATUS

reviewed

approved

#16 by Joerg Arndt at Sat Sep 24 05:09:37 EDT 2016

STATUS

proposed

reviewed

#15 by Michel Marcus at Thu Sep 22 09:58:56 EDT 2016

STATUS

editing

proposed

#14 by Michel Marcus at Thu Sep 22 09:58:31 EDT 2016

CROSSREFS

Cf. A276901-, A276902, A276903, A276904.

KEYWORD

nonn,more,changed

STATUS

proposed

editing

Discussion

Thu Sep 22

09:58

Michel Marcus: To give better search results.

#13 by Omar E. Pol at Thu Sep 22 09:36:00 EDT 2016

STATUS

editing

proposed

#12 by Omar E. Pol at Thu Sep 22 09:35:55 EDT 2016

CROSSREFS

Cf. A276901-A276904.

STATUS

proposed

editing

#11 by Omar E. Pol at Thu Sep 22 09:28:15 EDT 2016

STATUS

editing

proposed

#10 by Omar E. Pol at Thu Sep 22 09:26:57 EDT 2016

NAME

Number of positive walks with n steps {-3,-2,-1,1,2,3} starting at the origin, ending at altitude 1, and staying strictly above the x-axis.

STATUS

proposed

editing