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A081932
Sum of n-th row of A081930.
3
0, 33, 333, 4664, 51005, 616506, 7021007, 80308008, 900360009, 10004950010, 110005510011, 1200070620012, 13000078300013, 140000961400014, 1500001055000015, 16000012606000016, 170000013670000017, 1800000160380000018, 19000000171900000019, 200000001991000000020
OFFSET
1,2
MAPLE
isA002113 := proc(n) local digrev, d ; digrev := convert(n, base, 10) ; for d from 1 to nops(digrev)/2 do if op(d, digrev) <> op(-d, digrev) then RETURN(false) ; fi ; od ; RETURN(true) ; end: A081930 := proc(n) local a, k ; a := [] ; k := 10^(n-1) ; while nops(a) < n do if isA002113(k) then a := [op(a), k] ; fi ; k := k+1 ; od ; RETURN(a) ; end: A081932 := proc(n) local nrow, i ; nrow := A081930(n) ; add(op(i, nrow), i=1..nops(nrow)) ; end: for n from 1 to 18 do A081932(n) ; od ; # R. J. Mathar, Apr 05 2007
PROG
(Python)
def A081930(n, k):
s = str(10**((n-1)//2)-(n==1)+k-1)
return int(s+s[-1-n%2::-1])
def A081932(n):
return sum(A081930(n, k) for k in range(1, n+1)) # Pontus von Brömssen, Aug 24 2024
CROSSREFS
Sequence in context: A210077 A210070 A258638 * A121994 A093743 A279638
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Apr 01 2003
EXTENSIONS
More terms from R. J. Mathar, Apr 05 2007
More terms from Pontus von Brömssen, Aug 22 2024
a(1) corrected by Pontus von Brömssen, Aug 24 2024
STATUS
approved