A081932 Sum of n-th row of A081930.

0, 33, 333, 4664, 51005, 616506, 7021007, 80308008, 900360009, 10004950010, 110005510011, 1200070620012, 13000078300013, 140000961400014, 1500001055000015, 16000012606000016, 170000013670000017, 1800000160380000018, 19000000171900000019, 200000001991000000020

Offset

1,2

Links

Table of n, a(n) for n=1..20.

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

Cf. A081930, A081931.

Sequence in context: A210077 A210070 A258638 * A121994 A093743 A279638

Adjacent sequences: A081929 A081930 A081931 * A081933 A081934 A081935

Keyword

base,nonn,changed

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